Making r4 theme want no seethrough backround for 1 picture

I'm making a themes for my r4, but i want to remove a white backround and make it seethrough to show the the backround behind it.can anyone tell me how.

you need to use transparancy, however I doubt the r4 supports graphic formats that can do transparancy (.gif or .png)

Well if you want to show the background behind it (being a visible background) why not just save all the trouble and just use that? But, the R4 and most flashcarts use .bmp, and you can't use other image formats, I haven't been able to find anything specified in the .ini to load from them.

dont worry i found out how hehe, i used an image editing software, removed the specific colors or color then i used r4 skin making tool by alice. :P