I placed some animated GIFs with transparent backgrounds on my home page. When I then press the button, the color on the GIF reverses (good) but the transparent background also reverses and becomes a color(bad). Why does the transparent background of the GIF become an opaque color when pressed and is there any way to prevent this? The buttons would look really cool if the icon reversed and the background remained transparent.

It becomes opaque because it is set to "invert before image". I guess the opposite of transparent is not transparent. Fix this by unchecking that box. In your graphics program, invert the image. Make sure every layer is inverted. Save it and import it as the after image. That should do what you want

Of course, that worked like a charm. Thanks so much for pointing out the obvious!