Help! I'm totally confused!

I have navigation buttons with little icons. I'm using VFP8 with SP1 Loaded on a Windows XP machine.

My problem is that when I use .GIFS with transparent backgrounds the background appears white! When I use .BMP (no .MSK) the background is transparent.

I've read a number of threads here about this but can't find a conclusive solution.

Why don't my .GIFS work? can I rely on the .BMPs working without .MSKs ??
I've tried making the GIFS in PaintShop and in PhotoShop.

Any Ideas?


Gary