I posted this in response to a journal a few minutes ago, and so decided to paste it onto mine as well in case anybody wants to know how to make backgrounds transparent in the free art program; GIMP.

I simply go up to and select Layer, then Transparency, and make sure that "Add Alpha Channel" is on (if it's clickable, it's not--if it's greyed out, it is.)
Then use the Magic Wand tool (U key shortcut) and click on the background, then right click over that selected area and choose Edit, and then Cut (ctrl+x key shortcut.) Then that part of the background with revert to a grey checkerboard backround which represents transparency. Repeat on every section you want transparent. If already animated, simple click on each frame and follow the steps above.

A much faster and easier way to this is to first select Layer, then Transparency again. But now select Color to Alpha..., and after clicking Okay--it will search out your selected color (default white) and turn anything of that color and make it transparent. BUT, this is not recommended AT ALL for work that even has any shades of white to mid grey (maybe even other light shades of color) in it, as the program will read them as white and make those transparent as well.

So I usually use the first steps for pixel art, and the later for lineart.

Hope this helps.