Don't know, but even Windows Paint will allow you to save a picture out as a bitmap file. When saving, select 256 color bitmap as your file type. In addition, you can save DVD covers from the internet (from Amazon etc.) as bitmaps as well, right click, save picture as, and select .bmp. You can then resize using Windows Paint as well. Getting a bitmap isn't really the problem, it's finding a program that will do a good job of resizing and giving good results Paint may not yeild a satisfactory image.
EDIT: If interested in creating your own, you might also check out Daniel's article here:
[Link: remotecentral.com], on graphics.