Add and utilize TryGetValue on ExifProfile

src/ImageSharp/Formats/Jpeg/GolangPort/OrigJpegDecoderCore.cs

@@ -427,10 +427,13 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort
         {
             if (this.isExif)
             {
-                ExifValue horizontal = this.MetaData.ExifProfile.GetValue(ExifTag.XResolution);
+                double horizontalValue = this.MetaData.ExifProfile.TryGetValue(ExifTag.XResolution, out var horizonalTag)
-                ExifValue vertical = this.MetaData.ExifProfile.GetValue(ExifTag.YResolution);
+                    ? ((Rational)horizonalTag.Value).ToDouble() 
-                double horizontalValue = horizontal != null ? ((Rational)horizontal.Value).ToDouble() : 0;
+                    : 0;
-                double verticalValue = vertical != null ? ((Rational)vertical.Value).ToDouble() : 0;
+
+                double verticalValue = this.MetaData.ExifProfile.TryGetValue(ExifTag.YResolution, out var verticalTag)
+                    ? ((Rational)verticalTag.Value).ToDouble() 
+                    : 0;
 
                 if (horizontalValue > 0 && verticalValue > 0)
                 {

src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs

@@ -380,10 +380,13 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort
         {
             if (this.isExif)
             {
-                ExifValue horizontal = image.MetaData.ExifProfile.GetValue(ExifTag.XResolution);
+                double horizontalValue = image.MetaData.ExifProfile.TryGetValue(ExifTag.XResolution, out var horizontalTag)
-                ExifValue vertical = image.MetaData.ExifProfile.GetValue(ExifTag.YResolution);
+                    ? ((Rational)horizontalTag.Value).ToDouble() 
-                double horizontalValue = horizontal != null ? ((Rational)horizontal.Value).ToDouble() : 0;
+                    : 0;
-                double verticalValue = vertical != null ? ((Rational)vertical.Value).ToDouble() : 0;
+
+                double verticalValue = image.MetaData.ExifProfile.TryGetValue(ExifTag.YResolution, out var verticalTag)
+                    ? ((Rational)verticalTag.Value).ToDouble() 
+                    : 0;
 
                 if (horizontalValue > 0 && verticalValue > 0)
                 {

src/ImageSharp/MetaData/Profiles/Exif/ExifProfile.cs

@@ -160,6 +160,31 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif
             return null;
         }
 
+        /// <summary>
+        /// Conditionally the value of the tag if it exists.
+        /// </summary>
+        /// <param name="tag">The tag of the EXIF value.</param>
+        /// <param name="value">The value of the tag, if found.</param>
+        /// <returns>
+        /// The <see cref="bool"/>.
+        /// </returns>
+        public bool TryGetValue(ExifTag tag, out ExifValue value)
+        {
+            foreach (ExifValue exifValue in this.Values)
+            {
+                if (exifValue.Tag == tag)
+                {
+                    value = exifValue;
+
+                    return true;
+                }
+            }
+
+            value = default;
+
+            return false;
+        }
+
         /// <summary>
         /// Removes the value with the specified tag.
         /// </summary>

src/ImageSharp/MetaData/Profiles/Exif/ExifValue.cs

@@ -691,8 +691,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif
         /// <returns>The <see cref="string"/></returns>
         private string ToString(object value)
         {
-            string description = ExifTagDescriptionAttribute.GetDescription(this.Tag, value);
+            if (ExifTagDescriptionAttribute.GetDescription(this.Tag, value) is string description)
-            if (description != null)
             {
                 return description;
             }