One of my readers was having trouble with a signature image (bmp) on a report. It looked fine in preview but when printed the white background of the image printed as grey. After some research he found this post which showed him a relatively simple solution. He opened the bmp in an image editor and changed the colour depth of the image by reducing it from 24-bit to the simpler 256 colour depth. Apparently the background wasn’t quite white and the change forced the grey to ’round down’ to the nearest available colour in the palette which was white. If you use this method and you don’t get white you could go further. MS Paint goes down to 16 colors, and even down to monochrome (black and white).
Thanks to Jan Rymarz, a Crystal developer in the UK, for this tip, which is why I am writing about the colour grey instead of the color gray.