diff --git a/src/SixLabors.Core/Helpers/DebugGuard.cs b/src/SixLabors.Core/Helpers/DebugGuard.cs
index bfc2a7a8d6..c7fb796b3d 100644
--- a/src/SixLabors.Core/Helpers/DebugGuard.cs
+++ b/src/SixLabors.Core/Helpers/DebugGuard.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Diagnostics;
+using System.Runtime.CompilerServices;
 
 namespace SixLabors
 {
@@ -13,26 +14,47 @@ namespace SixLabors
     internal static class DebugGuard
     {
         /// <summary>
-        /// Verifies, that the method parameter with specified object value is not null
-        /// and throws an exception if it is found to be so.
+        /// Ensures that the value is not null.
         /// </summary>
-        /// <param name="target">The target object, which cannot be null.</param>
+        /// <param name="value">The target object, which cannot be null.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="target"/> is null.</exception>
-        /// <typeparam name="T">The type of the object to verify.</typeparam>
+        /// <typeparam name="TValue">The type of the value.</typeparam>
+        /// <exception cref="ArgumentNullException"><paramref name="value"/> is null.</exception>
         [Conditional("DEBUG")]
-        public static void NotNull<T>(T target, string parameterName)
-            where T : class
+        [DebuggerStepThrough]
+        public static void NotNull<TValue>(TValue value, string parameterName)
+            where TValue : class
         {
-            if (target is null)
+            if (value is null)
             {
-                throw new ArgumentNullException(parameterName);
+                ThrowArgumentNullException(parameterName);
             }
         }
 
         /// <summary>
-        /// Verifies that the specified value is less than a maximum value
-        /// and throws an exception if it is not.
+        /// Ensures that the target value is not null, empty, or whitespace.
+        /// </summary>
+        /// <param name="value">The target string, which should be checked against being null or empty.</param>
+        /// <param name="parameterName">Name of the parameter.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="value"/> is null.</exception>
+        /// <exception cref="ArgumentException"><paramref name="value"/> is empty or contains only blanks.</exception>
+        [Conditional("DEBUG")]
+        [DebuggerStepThrough]
+        public static void NotNullOrWhiteSpace(string value, string parameterName)
+        {
+            if (value is null)
+            {
+                ThrowArgumentNullException(parameterName);
+            }
+
+            if (string.IsNullOrWhiteSpace(value))
+            {
+                ThrowArgumentException("Must not be empty or whitespace.", parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Ensures that the specified value is less than a maximum value.
         /// </summary>
         /// <param name="value">The target value, which should be validated.</param>
         /// <param name="max">The maximum value.</param>
@@ -42,12 +64,13 @@ namespace SixLabors
         /// <paramref name="value"/> is greater than the maximum value.
         /// </exception>
         [Conditional("DEBUG")]
+        [DebuggerStepThrough]
         public static void MustBeLessThan<TValue>(TValue value, TValue max, string parameterName)
                     where TValue : IComparable<TValue>
         {
             if (value.CompareTo(max) >= 0)
             {
-                throw new ArgumentOutOfRangeException(parameterName, $"Value must be less than {max}.");
+                ThrowArgumentOutOfRangeException(parameterName, $"Value {value} must be less than {max}.");
             }
         }
 
@@ -63,12 +86,13 @@ namespace SixLabors
         /// <paramref name="value"/> is greater than the maximum value.
         /// </exception>
         [Conditional("DEBUG")]
+        [DebuggerStepThrough]
         public static void MustBeLessThanOrEqualTo<TValue>(TValue value, TValue max, string parameterName)
                     where TValue : IComparable<TValue>
         {
             if (value.CompareTo(max) > 0)
             {
-                throw new ArgumentOutOfRangeException(parameterName, $"Value must be less than or equal to {max}.");
+                ThrowArgumentOutOfRangeException(parameterName, $"Value {value} must be less than or equal to {max}.");
             }
         }
 
@@ -84,14 +108,15 @@ namespace SixLabors
         /// <paramref name="value"/> is less than the minimum value.
         /// </exception>
         [Conditional("DEBUG")]
+        [DebuggerStepThrough]
         public static void MustBeGreaterThan<TValue>(TValue value, TValue min, string parameterName)
             where TValue : IComparable<TValue>
         {
             if (value.CompareTo(min) <= 0)
             {
-                throw new ArgumentOutOfRangeException(
+                ThrowArgumentOutOfRangeException(
                     parameterName,
-                    $"Value must be greater than {min}.");
+                    $"Value {value} must be greater than {min}.");
             }
         }
 
@@ -107,33 +132,177 @@ namespace SixLabors
         /// <paramref name="value"/> is less than the minimum value.
         /// </exception>
         [Conditional("DEBUG")]
+        [DebuggerStepThrough]
         public static void MustBeGreaterThanOrEqualTo<TValue>(TValue value, TValue min, string parameterName)
             where TValue : IComparable<TValue>
         {
             if (value.CompareTo(min) < 0)
             {
-                throw new ArgumentOutOfRangeException(parameterName, $"Value must be greater than or equal to {min}.");
+                ThrowArgumentOutOfRangeException(parameterName, $"Value {value} must be greater than or equal to {min}.");
             }
         }
 
         /// <summary>
-        /// Verifies, that the `target` array has declared the length  or longer.
+        /// Verifies that the specified value is greater than or equal to a minimum value and less than
+        /// or equal to a maximum value and throws an exception if it is not.
         /// </summary>
-        /// <typeparam name="T">The element type of the spans.</typeparam>
-        /// <param name="target">The target array.</param>
-        /// <param name="minLength">The min length the array must have.</param>
+        /// <param name="value">The target value, which should be validated.</param>
+        /// <param name="min">The minimum value.</param>
+        /// <param name="max">The maximum value.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <typeparam name="TValue">The type of the value.</typeparam>
+        /// <exception cref="ArgumentException">
+        /// <paramref name="value"/> is less than the minimum value of greater than the maximum value.
+        /// </exception>
+        [Conditional("DEBUG")]
+        [DebuggerStepThrough]
+        public static void MustBeBetweenOrEqualTo<TValue>(TValue value, TValue min, TValue max, string parameterName)
+            where TValue : IComparable<TValue>
+        {
+            if (value.CompareTo(min) < 0 || value.CompareTo(max) > 0)
+            {
+                ThrowArgumentOutOfRangeException(parameterName, $"Value {value} must be greater than or equal to {min} and less than or equal to {max}.");
+            }
+        }
+
+        /// <summary>
+        /// Verifies, that the method parameter with specified target value is true
+        /// and throws an exception if it is found to be so.
+        /// </summary>
+        /// <param name="target">The target value, which cannot be false.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <param name="message">The error message, if any to add to the exception.</param>
+        /// <exception cref="ArgumentException">
+        /// <paramref name="target"/> is false.
+        /// </exception>
+        [Conditional("DEBUG")]
+        [DebuggerStepThrough]
+        public static void IsTrue(bool target, string parameterName, string message)
+        {
+            if (!target)
+            {
+                ThrowArgumentException(message, parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Verifies, that the method parameter with specified target value is false
+        /// and throws an exception if it is found to be so.
+        /// </summary>
+        /// <param name="target">The target value, which cannot be true.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <param name="message">The error message, if any to add to the exception.</param>
         /// <exception cref="ArgumentException">
         /// <paramref name="target"/> is true.
         /// </exception>
         [Conditional("DEBUG")]
-        public static void MustBeSizedAtLeast<T>(T[] target, int minLength, string parameterName)
-            where T : struct
+        [DebuggerStepThrough]
+        public static void IsFalse(bool target, string parameterName, string message)
         {
-            if (target.Length < minLength)
+            if (target)
             {
-                throw new ArgumentException($"The size must be at least {minLength}.", parameterName);
+                ThrowArgumentException(message, parameterName);
             }
         }
+
+        /// <summary>
+        /// Verifies, that the `source` span has the length of 'minLength', or longer.
+        /// </summary>
+        /// <typeparam name="T">The element type of the spans.</typeparam>
+        /// <param name="source">The source span.</param>
+        /// <param name="minLength">The minimum length.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <exception cref="ArgumentException">
+        /// <paramref name="source"/> has less than <paramref name="minLength"/> items.
+        /// </exception>
+        [Conditional("DEBUG")]
+        [DebuggerStepThrough]
+        public static void MustBeSizedAtLeast<T>(ReadOnlySpan<T> source, int minLength, string parameterName)
+        {
+            if (source.Length < minLength)
+            {
+                ThrowArgumentException($"Span-s must be at least of length {minLength}!", parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Verifies that the 'destination' span is not shorter than 'source'.
+        /// </summary>
+        /// <typeparam name="TSource">The source element type.</typeparam>
+        /// <typeparam name="TDest">The destination element type.</typeparam>
+        /// <param name="source">The source span.</param>
+        /// <param name="destination">The destination span.</param>
+        /// <param name="destinationParamName">The name of the argument for 'destination'.</param>
+        [Conditional("DEBUG")]
+        [DebuggerStepThrough]
+        public static void DestinationShouldNotBeTooShort<TSource, TDest>(
+            ReadOnlySpan<TSource> source,
+            Span<TDest> destination,
+            string destinationParamName)
+        {
+            if (destination.Length < source.Length)
+            {
+                ThrowArgumentException($"Destination span is too short!", destinationParamName);
+            }
+        }
+
+        /// <summary>
+        /// Verifies that the 'destination' span is not shorter than 'source'.
+        /// </summary>
+        /// <typeparam name="TSource">The source element type.</typeparam>
+        /// <typeparam name="TDest">The destination element type.</typeparam>
+        /// <param name="source">The source span.</param>
+        /// <param name="destination">The destination span.</param>
+        /// <param name="destinationParamName">The name of the argument for 'destination'.</param>
+        [Conditional("DEBUG")]
+        [DebuggerStepThrough]
+        public static void DestinationShouldNotBeTooShort<TSource, TDest>(
+            Span<TSource> source,
+            Span<TDest> destination,
+            string destinationParamName)
+        {
+            if (destination.Length < source.Length)
+            {
+                ThrowArgumentException($"Destination span is too short!", destinationParamName);
+            }
+        }
+
+        /// <summary>
+        /// Verifies, that the `source` span has the length of 'minLength', or longer.
+        /// </summary>
+        /// <typeparam name="T">The element type of the spans.</typeparam>
+        /// <param name="source">The target span.</param>
+        /// <param name="minLength">The minimum length.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <exception cref="ArgumentException">
+        /// <paramref name="source"/> has less than <paramref name="minLength"/> items.
+        /// </exception>
+        [Conditional("DEBUG")]
+        [DebuggerStepThrough]
+        public static void MustBeSizedAtLeast<T>(Span<T> source, int minLength, string parameterName)
+        {
+            if (source.Length < minLength)
+            {
+                ThrowArgumentException($"Span-s must be at least of length {minLength}!", parameterName);
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowArgumentException(string message, string parameterName)
+        {
+            throw new ArgumentException(message, parameterName);
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowArgumentOutOfRangeException(string parameterName, string message)
+        {
+            throw new ArgumentOutOfRangeException(parameterName, message);
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowArgumentNullException(string parameterName)
+        {
+            throw new ArgumentNullException(parameterName);
+        }
     }
 }
\ No newline at end of file
diff --git a/src/SixLabors.Core/Helpers/Guard.cs b/src/SixLabors.Core/Helpers/Guard.cs
index d6616aa78e..09c8675d3a 100644
--- a/src/SixLabors.Core/Helpers/Guard.cs
+++ b/src/SixLabors.Core/Helpers/Guard.cs
@@ -4,7 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
+using System.Runtime.CompilerServices;
 
 namespace SixLabors
 {
@@ -15,22 +15,63 @@ namespace SixLabors
     internal static class Guard
     {
         /// <summary>
-        /// Verifies that the specified value is less than a maximum value
-        /// and throws an exception if it is not.
+        /// Ensures that the value is not null.
+        /// </summary>
+        /// <param name="value">The target object, which cannot be null.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <typeparam name="TValue">The type of the value.</typeparam>
+        /// <exception cref="ArgumentNullException"><paramref name="value"/> is null.</exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
+        public static void NotNull<TValue>(TValue value, string parameterName)
+            where TValue : class
+        {
+            if (value is null)
+            {
+                ThrowArgumentNullException(parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Ensures that the target value is not null, empty, or whitespace.
+        /// </summary>
+        /// <param name="value">The target string, which should be checked against being null or empty.</param>
+        /// <param name="parameterName">Name of the parameter.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="value"/> is null.</exception>
+        /// <exception cref="ArgumentException"><paramref name="value"/> is empty or contains only blanks.</exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
+        public static void NotNullOrWhiteSpace(string value, string parameterName)
+        {
+            if (value is null)
+            {
+                ThrowArgumentNullException(parameterName);
+            }
+
+            if (string.IsNullOrWhiteSpace(value))
+            {
+                ThrowArgumentException("Must not be empty or whitespace.", parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Ensures that the specified value is less than a maximum value.
         /// </summary>
         /// <param name="value">The target value, which should be validated.</param>
         /// <param name="max">The maximum value.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
         /// <typeparam name="TValue">The type of the value.</typeparam>
-        /// <exception cref="ArgumentOutOfRangeException">
+        /// <exception cref="ArgumentException">
         /// <paramref name="value"/> is greater than the maximum value.
         /// </exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
         public static void MustBeLessThan<TValue>(TValue value, TValue max, string parameterName)
-            where TValue : IComparable<TValue>
+                    where TValue : IComparable<TValue>
         {
             if (value.CompareTo(max) >= 0)
             {
-                throw new ArgumentOutOfRangeException(parameterName, $"Value must be less than {max}.");
+                ThrowArgumentOutOfRangeException(parameterName, $"Value {value} must be less than {max}.");
             }
         }
 
@@ -42,15 +83,17 @@ namespace SixLabors
         /// <param name="max">The maximum value.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
         /// <typeparam name="TValue">The type of the value.</typeparam>
-        /// <exception cref="ArgumentOutOfRangeException">
+        /// <exception cref="ArgumentException">
         /// <paramref name="value"/> is greater than the maximum value.
         /// </exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
         public static void MustBeLessThanOrEqualTo<TValue>(TValue value, TValue max, string parameterName)
-            where TValue : IComparable<TValue>
+                    where TValue : IComparable<TValue>
         {
             if (value.CompareTo(max) > 0)
             {
-                throw new ArgumentOutOfRangeException(parameterName, $"Value must be less than or equal to {max}.");
+                ThrowArgumentOutOfRangeException(parameterName, $"Value {value} must be less than or equal to {max}.");
             }
         }
 
@@ -62,15 +105,19 @@ namespace SixLabors
         /// <param name="min">The minimum value.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
         /// <typeparam name="TValue">The type of the value.</typeparam>
-        /// <exception cref="ArgumentOutOfRangeException">
+        /// <exception cref="ArgumentException">
         /// <paramref name="value"/> is less than the minimum value.
         /// </exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
         public static void MustBeGreaterThan<TValue>(TValue value, TValue min, string parameterName)
             where TValue : IComparable<TValue>
         {
             if (value.CompareTo(min) <= 0)
             {
-                throw new ArgumentOutOfRangeException(parameterName, $"Value must be greater than {min}.");
+                ThrowArgumentOutOfRangeException(
+                    parameterName,
+                    $"Value {value} must be greater than {min}.");
             }
         }
 
@@ -82,15 +129,17 @@ namespace SixLabors
         /// <param name="min">The minimum value.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
         /// <typeparam name="TValue">The type of the value.</typeparam>
-        /// <exception cref="ArgumentOutOfRangeException">
+        /// <exception cref="ArgumentException">
         /// <paramref name="value"/> is less than the minimum value.
         /// </exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
         public static void MustBeGreaterThanOrEqualTo<TValue>(TValue value, TValue min, string parameterName)
             where TValue : IComparable<TValue>
         {
             if (value.CompareTo(min) < 0)
             {
-                throw new ArgumentOutOfRangeException(parameterName, $"Value must be greater than or equal to {min}.");
+                ThrowArgumentOutOfRangeException(parameterName, $"Value {value} must be greater than or equal to {min}.");
             }
         }
 
@@ -103,34 +152,158 @@ namespace SixLabors
         /// <param name="max">The maximum value.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
         /// <typeparam name="TValue">The type of the value.</typeparam>
-        /// <exception cref="ArgumentOutOfRangeException">
+        /// <exception cref="ArgumentException">
         /// <paramref name="value"/> is less than the minimum value of greater than the maximum value.
         /// </exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
         public static void MustBeBetweenOrEqualTo<TValue>(TValue value, TValue min, TValue max, string parameterName)
             where TValue : IComparable<TValue>
         {
             if (value.CompareTo(min) < 0 || value.CompareTo(max) > 0)
             {
-                throw new ArgumentOutOfRangeException(parameterName, $"Value must be greater than or equal to {min} and less than or equal to {max}.");
+                ThrowArgumentOutOfRangeException(parameterName, $"Value {value} must be greater than or equal to {min} and less than or equal to {max}.");
+            }
+        }
+
+        /// <summary>
+        /// Verifies, that the method parameter with specified target value is true
+        /// and throws an exception if it is found to be so.
+        /// </summary>
+        /// <param name="target">The target value, which cannot be false.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <param name="message">The error message, if any to add to the exception.</param>
+        /// <exception cref="ArgumentException">
+        /// <paramref name="target"/> is false.
+        /// </exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
+        public static void IsTrue(bool target, string parameterName, string message)
+        {
+            if (!target)
+            {
+                ThrowArgumentException(message, parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Verifies, that the method parameter with specified target value is false
+        /// and throws an exception if it is found to be so.
+        /// </summary>
+        /// <param name="target">The target value, which cannot be true.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <param name="message">The error message, if any to add to the exception.</param>
+        /// <exception cref="ArgumentException">
+        /// <paramref name="target"/> is true.
+        /// </exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
+        public static void IsFalse(bool target, string parameterName, string message)
+        {
+            if (target)
+            {
+                ThrowArgumentException(message, parameterName);
             }
         }
 
         /// <summary>
-        /// Verifies, that the `target` span has the length of 'minLength', or longer.
+        /// Verifies, that the `source` span has the length of 'minLength', or longer.
         /// </summary>
         /// <typeparam name="T">The element type of the spans.</typeparam>
-        /// <param name="value">The target span.</param>
+        /// <param name="source">The source span.</param>
         /// <param name="minLength">The minimum length.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
         /// <exception cref="ArgumentException">
-        /// The length of <paramref name="value"/> is less than <paramref name="minLength"/>.
+        /// <paramref name="source"/> has less than <paramref name="minLength"/> items.
         /// </exception>
-        public static void MustBeSizedAtLeast<T>(T[] value, int minLength, string parameterName)
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
+        public static void MustBeSizedAtLeast<T>(ReadOnlySpan<T> source, int minLength, string parameterName)
         {
-            if (value.Length < minLength)
+            if (source.Length < minLength)
             {
-                throw new ArgumentException($"The size must be at least {minLength}.", parameterName);
+                ThrowArgumentException($"Span-s must be at least of length {minLength}!", parameterName);
             }
         }
+
+        /// <summary>
+        /// Verifies, that the `source` span has the length of 'minLength', or longer.
+        /// </summary>
+        /// <typeparam name="T">The element type of the spans.</typeparam>
+        /// <param name="source">The target span.</param>
+        /// <param name="minLength">The minimum length.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <exception cref="ArgumentException">
+        /// <paramref name="source"/> has less than <paramref name="minLength"/> items.
+        /// </exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
+        public static void MustBeSizedAtLeast<T>(Span<T> source, int minLength, string parameterName)
+        {
+            if (source.Length < minLength)
+            {
+                ThrowArgumentException($"The size must be at least {minLength}.", parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Verifies that the 'destination' span is not shorter than 'source'.
+        /// </summary>
+        /// <typeparam name="TSource">The source element type.</typeparam>
+        /// <typeparam name="TDest">The destination element type.</typeparam>
+        /// <param name="source">The source span.</param>
+        /// <param name="destination">The destination span.</param>
+        /// <param name="destinationParamName">The name of the argument for 'destination'.</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
+        public static void DestinationShouldNotBeTooShort<TSource, TDest>(
+            ReadOnlySpan<TSource> source,
+            Span<TDest> destination,
+            string destinationParamName)
+        {
+            if (destination.Length < source.Length)
+            {
+                ThrowArgumentException($"Destination span is too short!", destinationParamName);
+            }
+        }
+
+        /// <summary>
+        /// Verifies that the 'destination' span is not shorter than 'source'.
+        /// </summary>
+        /// <typeparam name="TSource">The source element type.</typeparam>
+        /// <typeparam name="TDest">The destination element type.</typeparam>
+        /// <param name="source">The source span.</param>
+        /// <param name="destination">The destination span.</param>
+        /// <param name="destinationParamName">The name of the argument for 'destination'.</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [DebuggerStepThrough]
+        public static void DestinationShouldNotBeTooShort<TSource, TDest>(
+            Span<TSource> source,
+            Span<TDest> destination,
+            string destinationParamName)
+        {
+            if (destination.Length < source.Length)
+            {
+                ThrowArgumentException($"Destination span is too short!", destinationParamName);
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowArgumentException(string message, string parameterName)
+        {
+            throw new ArgumentException(message, parameterName);
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowArgumentOutOfRangeException(string parameterName, string message)
+        {
+            throw new ArgumentOutOfRangeException(parameterName, message);
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowArgumentNullException(string parameterName)
+        {
+            throw new ArgumentNullException(parameterName);
+        }
     }
-}
\ No newline at end of file
+}
diff --git a/tests/SixLabors.Core.Tests/Helpers/GuardTests.cs b/tests/SixLabors.Core.Tests/Helpers/GuardTests.cs
index d6ef967b83..bed743767a 100644
--- a/tests/SixLabors.Core.Tests/Helpers/GuardTests.cs
+++ b/tests/SixLabors.Core.Tests/Helpers/GuardTests.cs
@@ -8,6 +8,96 @@ namespace SixLabors.Helpers.Tests
 {
     public class GuardTests
     {
+        private class Foo
+        {
+        }
+
+        [Fact]
+        public void NotNull_WhenNull_Throws()
+        {
+            Foo foo = null;
+            Assert.Throws<ArgumentNullException>(() => Guard.NotNull(foo, nameof(foo)));
+        }
+
+        [Fact]
+        public void NotNull_NotNull()
+        {
+            Foo foo = new Foo();
+            Guard.NotNull(foo, nameof(foo));
+        }
+
+        [Theory]
+        [InlineData(null, true)]
+        [InlineData("", true)]
+        [InlineData("  ", true)]
+        [InlineData("$", false)]
+        [InlineData("lol", false)]
+        public void NotNullOrWhiteSpace(string str, bool shouldThrow)
+        {
+            if (shouldThrow)
+            {
+                Assert.ThrowsAny<ArgumentException>(() => Guard.NotNullOrWhiteSpace(str, nameof(str)));
+            }
+            else
+            {
+                Guard.NotNullOrWhiteSpace(str, nameof(str));
+            }
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void IsTrue(bool value)
+        {
+            if (!value)
+            {
+                Assert.Throws<ArgumentException>(() => Guard.IsTrue(value, nameof(value), "Boo!"));
+            }
+            else
+            {
+                Guard.IsTrue(value, nameof(value), "Boo.");
+            }
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void IsFalse(bool value)
+        {
+            if (value)
+            {
+                Assert.Throws<ArgumentException>(() => Guard.IsFalse(value, nameof(value), "Boo!"));
+            }
+            else
+            {
+                Guard.IsFalse(value, nameof(value), "Boo.");
+            }
+        }
+
+        [Theory]
+        [InlineData(0, 0, false)]
+        [InlineData(1, 1, false)]
+        [InlineData(1, 0, false)]
+        [InlineData(13, 13, false)]
+        [InlineData(20, 13, false)]
+        [InlineData(12, 13, true)]
+        [InlineData(0, 1, true)]
+        public void MustBeSizedAtLeast(int length, int minLength, bool shouldThrow)
+        {
+            int[] data = new int[length];
+
+            if (shouldThrow)
+            {
+                Assert.Throws<ArgumentException>(() => Guard.MustBeSizedAtLeast((Span<int>)data, minLength, nameof(data)));
+                Assert.Throws<ArgumentException>(() => Guard.MustBeSizedAtLeast((ReadOnlySpan<int>)data, minLength, nameof(data)));
+            }
+            else
+            {
+                Guard.MustBeSizedAtLeast((Span<int>)data, minLength, nameof(data));
+                Guard.MustBeSizedAtLeast((ReadOnlySpan<int>)data, minLength, nameof(data));
+            }
+        }
+
         [Fact]
         public void MustBeLessThan_IsLess_ThrowsNoException()
         {
@@ -25,7 +115,7 @@ namespace SixLabors.Helpers.Tests
             });
 
             Assert.Equal("myParamName", exception.ParamName);
-            Assert.Contains($"Value must be less than {max}.", exception.Message);
+            Assert.Contains($"Value {value} must be less than {max}.", exception.Message);
         }
 
         [Theory]
@@ -45,7 +135,7 @@ namespace SixLabors.Helpers.Tests
             });
 
             Assert.Equal("myParamName", exception.ParamName);
-            Assert.Contains($"Value must be less than or equal to 1.", exception.Message);
+            Assert.Contains($"Value 2 must be less than or equal to 1.", exception.Message);
         }
 
         [Fact]
@@ -65,7 +155,7 @@ namespace SixLabors.Helpers.Tests
             });
 
             Assert.Equal("myParamName", exception.ParamName);
-            Assert.Contains($"Value must be greater than {min}.", exception.Message);
+            Assert.Contains($"Value {value} must be greater than {min}.", exception.Message);
         }
 
         [Theory]
@@ -85,7 +175,7 @@ namespace SixLabors.Helpers.Tests
             });
 
             Assert.Equal("myParamName", exception.ParamName);
-            Assert.Contains($"Value must be greater than or equal to 2.", exception.Message);
+            Assert.Contains($"Value 1 must be greater than or equal to 2.", exception.Message);
         }
 
         [Theory]
@@ -108,7 +198,7 @@ namespace SixLabors.Helpers.Tests
             });
 
             Assert.Equal("myParamName", exception.ParamName);
-            Assert.Contains($"Value must be greater than or equal to {min} and less than or equal to {max}.", exception.Message);
+            Assert.Contains($"Value {value} must be greater than or equal to {min} and less than or equal to {max}.", exception.Message);
         }
 
         [Theory]
@@ -128,7 +218,7 @@ namespace SixLabors.Helpers.Tests
             });
 
             Assert.Equal("myParamName", exception.ParamName);
-            Assert.Contains("The size must be at least 3.", exception.Message);
+            Assert.Contains("The size must be at least 3", exception.Message);
         }
     }
 }