The sig image fits fine to me, but it might be good to shrink it down a bit. It wouldn't lose any detail really and it would probably save on load time as well.
I don't mind scrolling past it at all, it's just that it might help people with dialup to load the page a second faster. I know you can just say "oh well get a new computer and net connection" but this stuff costs money which not everyone can afford. It doesn't cost all that much just to use the internet. When I got my first computer I bought it for 75 dollars and it was like a 75mhz with a dial-up connection and a 13" screen.
The point I'm trying to make is that just because people are posting on the forums and have a computer doesn't mean they are rich enough to buy better equipment.