BitmapData / PixelFormat HELP

Question

This line of code originally compiled for a PC, but won't compile for a Pocket PC device:

// Get a pointer to the image data
System.Drawing.Imaging.BitmapData imageData = ImageFile.LockBits(new System.Drawing.Rectangle(0, 0, ImageFile.Width, ImageFile.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, ImageFile.PixelFormat);

Error message:
error CS0117: 'System.Drawing.Bitmap' does not contain a definition for 'PixelFormat'

Is there another way I can rewrite this line of code so it works for the Pocket PC?

Thanks