fix comments

src/ImageSharp/Formats/Bmp/BmpConstants.cs

@@ -18,7 +18,7 @@ namespace ImageSharp.Formats
         public static readonly IEnumerable<string> MimeTypes = new[] { "image/bmp", "image/x-windows-bmp" };
 
         /// <summary>
-        /// The list of mimetypes that equate to a bmp
+        /// The list of file extensions that equate to a bmp
         /// </summary>
         public static readonly IEnumerable<string> FileExtensions = new[] { "bm", "bmp", "dip" };
     }

src/ImageSharp/Formats/Gif/GifConstants.cs

@@ -99,7 +99,7 @@ namespace ImageSharp.Formats
         public static readonly IEnumerable<string> MimeTypes = new[] { "image/gif" };
 
         /// <summary>
-        /// The list of mimetypes that equate to a bmp
+        /// The list of file extensions that equate to a bmp
         /// </summary>
         public static readonly IEnumerable<string> FileExtensions = new[] { "gif" };
     }

src/ImageSharp/Formats/Jpeg/JpegConstants.cs

@@ -23,7 +23,7 @@ namespace ImageSharp.Formats
         public static readonly IEnumerable<string> MimeTypes = new[] { "image/jpeg", "image/pjpeg" };
 
         /// <summary>
-        /// The list of mimetypes that equate to a jpeg
+        /// The list of file extensions that equate to a jpeg
         /// </summary>
         public static readonly IEnumerable<string> FileExtensions = new[] { "jpg", "jpeg", "jfif" };
 

src/ImageSharp/Formats/Png/PngConstants.cs

@@ -23,7 +23,7 @@ namespace ImageSharp.Formats
         public static readonly IEnumerable<string> MimeTypes = new[] { "image/png" };
 
         /// <summary>
-        /// The list of mimetypes that equate to a jpeg
+        /// The list of file extensions that equate to a jpeg
         /// </summary>
         public static readonly IEnumerable<string> FileExtensions = new[] { "png" };
     }

tests/ImageSharp.Tests/ConfigurationTests.cs

@@ -27,7 +27,7 @@ namespace ImageSharp.Tests
         public ConfigurationTests()
         {
             this.DefaultConfiguration = Configuration.CreateDefaultInstance();
-            this.ConfigurationEmpty = Configuration.CreateDefaultInstance();
+            this.ConfigurationEmpty = new Configuration();
         }
 
         [Fact]