remove unneeded public constants

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -120,11 +120,11 @@ namespace SixLabors.ImageSharp.Formats
                     this.currentStream.Read(palette, 0, colorMapSize);
                 }
 
-                if (this.infoHeader.Width > Image<TPixel>.MaxWidth || this.infoHeader.Height > Image<TPixel>.MaxHeight)
+                if (this.infoHeader.Width > int.MaxValue || this.infoHeader.Height > int.MaxValue)
                 {
                     throw new ArgumentOutOfRangeException(
                         $"The input bitmap '{this.infoHeader.Width}x{this.infoHeader.Height}' is "
-                        + $"bigger then the max allowed size '{Image<TPixel>.MaxWidth}x{Image<TPixel>.MaxHeight}'");
+                        + $"bigger then the max allowed size '{int.MaxValue}x{int.MaxValue}'");
                 }
 
                 Image<TPixel> image = new Image<TPixel>(this.configuration, this.infoHeader.Width, this.infoHeader.Height);

src/ImageSharp/Image/ImageBase{TPixel}.cs

@@ -19,16 +19,6 @@ namespace SixLabors.ImageSharp
     public abstract class ImageBase<TPixel> : IImageBase<TPixel>
         where TPixel : struct, IPixel<TPixel>
     {
-        /// <summary>
-        /// Gets or sets the maximum allowable width in pixels.
-        /// </summary>
-        public const int MaxWidth = int.MaxValue;
-
-        /// <summary>
-        /// Gets or sets the maximum allowable height in pixels.
-        /// </summary>
-        public const int MaxHeight = int.MaxValue;
-
 #pragma warning disable SA1401 // Fields must be private
         /// <summary>
         /// The image pixels. Not private as Buffer2D requires an array in its constructor.