In WinCE device should always 24 bit images used?

gistfile1.cs

// image : 32 Bit 
image.GetImageInfo(out imageInfo);

// imageInfo.PixelFormat = PixelFormat.Format32bppRgb detected

// Without this line thumbnail is black image 
imageInfo.PixelFormat = PixelFormat.Format24bppRgb;

// http://msdn.microsoft.com/en-us/library/aa452205.aspx
// A PixelFormatID value that specifies the numerical format of the pixels in the image. 
// For more information, see PixelFormat Values.
// Set this value to PixelFormatDontCare to create a new bitmap image that has the same pixel format as the source image. 
IImagingFactory.CreateBitmapFromImage(image, (uint)width, (uint)height, 
  imageInfo.PixelFormat, InterpolationHint.InterpolationHintDefault, out thumbnail);
  
// thumbnail is now correct both for 24-Bit and 32-Bit images