Problem with Graffiti program.

I have attached a Graffiti program. It uses Modified version 'Sprite', which I downloaded from Fox's site. Anyway the Sprite control uses Mask Picture property of User Control to make a color invisible. The problem is that when I add a Graffito to the program screen, It gets saved as a 24-Bit Bitmap. Hence the sprite does not make the White Color area to be invisible. But when I open the Program created Bitmap in MS-Paint and save it as 256-Color Bitmap, then the white color is invisible.
Any Solutions. Thanks in advance.

Any comments on the program... please!