That's not exactly what I meant by bitmaps, sorry if I used the wrong phrasing, I'm using png and jpg for pretty much everything.
Anyway, the primary reason is saving space, like I said, I'm using a lot of large graphics, some of them are over 500 pixels and higher, so I'm wondering if a script that would allow a single frame rather then multiple frames is possible, but as an alternate.
For most of the larger overlay graphics I can always use the multiple fog scripts, but there are some places where I'd rather not because those scripts are already being used on the map.
Also, I'm using parallax backgrounds on pretty much every map, so my game is rather large as it is.
The other reason is as you said, I'm using a lot of different sized images.
Now that you mention it, animation is actually another reason, but for different reasons, several of the sprites on my maps use animations through character graphics changes, so a single frame would be nice for those as well, since the next animation is on a different graphic.
It's ok, I understand exactly what your saying, I just suck really badly when scripts are concerned.