Middle Age Geeks

I've tried to put up some signatures that were rejected by the site. They apparently had too many characters. I forget the exact limit. But I see sigs that have entire images in them, why can't my attempted sigs have more characters even though they use less space?
Sorry to bithc, I know it's a small thing. Just sometimes maddening.

The signature has to be under 200 in size or 255 chars long. Otherwise it should show up.