I don't know that we have stated too much here in the Sylvan Heart forums, but it was mentioned a few times in the Sylvan Dreams forums. The size of your signature picture, the one at the bottom of your posts, should be around the size of 400x200. Try to stay within that range and not get much bigger. You can tell the size of a sig by right clicking the picture, going to the bottom, and clicking on properties.
Bumping this post up for our many new players or members just getting signiture pictures.