Bigger images are probably hosted elsewhere. My sig pic is on my site's server. Are you familiar with the vB tags? Say, in a post you want to display an image from elsewhere IN the post rather than as an attachment...you would use the code:
[ i m g ]http://wherever.com/something.jpb/gif/etc[ / i m g ]
But without the spaces on the start/end tags. Same goes for the signature. Just toss in the tags and the URL for the image in your sig text and BAM, there it is.
If you have a pic you want to use, email it to me and I will host it for ya. Same goes for anyone here.