Yeah, I agree with doc's last comment. People who do allot of GFX and who are good at it, can at times make rather complicated sigs (or poorly put together ones if you're a n00b
). I've had it happen many times, there are alternatives like PNG Crush, but such alternatives are complicated for some.
I don't think we will get a bigger limit anytime soon. Maybe in V2? The problem I see is that it will take longer to load pages (and there are people who still use 56k, hence the 56k warning on picture based topics). I don't know if it would strain the server itself as much, because all these sigs are hosted and using the bandwidth of their respective Image Uploader provider. The only thing that bothers me really is that avatars practically have no limit, and some people are not very good at making GIFs. You can see ones that are huge MB munchers and make a page a b*tch to load. I'd rather want to see a restriction in file size
for avatars instead if I'm honest
Oh and 500x150 is very small. It's so hard to put detail in such a small area. Mind you , it's to prevent users making huge-ass irrelevant sigs.