When you post your photos or you have a signature that may be very large when you post. I have found a new site that crops and re-sizes your photos.
Here is the link, Snipshot
It's a free site and really easy to manage your photos.

what are the rules (if any) concerning sig and pic sizes?

There aren't really any size rules here but sometimes when a photo is posted with text,you can't read or see the whole post.
We have unlimited bandwith on EG.

Got a new code that shrinks pictures automatically.