public static ImageSource Resize(this ImageSource image, Size maxSize)
{
var rasterImage = ToRasterImage(image);
var currentSize = new Size(rasterImage.ImageSize.Width, rasterImage.ImageSize.Height);
var newSize = currentSize.PreserveAspectRatioWithinBounds(maxSize);
var destImage = new RasterImage(
RasterMemoryFlags.Conventional,
(int)newSize.Width,
(int)newSize.Height,
rasterImage.BitsPerPixel,
rasterImage.Order,
rasterImage.ViewPerspective,
rasterImage.GetPalette(),
IntPtr.Zero,
0);
var cmd = new ResizeCommand(destImage, RasterSizeFlags.Bicubic);
cmd.Run(rasterImage);
return ToBitmapSource(destImage);
}