To get pictures in your signature, the first thing you need to do is upload some pics to a site that allows remote viewing like www.imagestation.com
I copied the following post from the "How to post pictures" thread which is a sticky at the top of the New Cats On The Block forum. I hope it helps, if you have any other questions please let us know.
"Pictures in Your Signature
Putting pictures in your signature lines is easy once you get the remote linking thing figured out.
Remote linking is the ONLY way to post pictures in your signature.
When you are logged in, click the User CP[/b} button at the top of the forum, then [b]Edit Profile. About halfway down is where you put whatever you want into your signature. To put a picture there, follow the instructions in the first 2 posts of this thread for Remote Linking. The only difference is that you have to manually type in the [IMG ]....[/IMG ] (no spaces in the brackets) around the web address where your picture can be found.
At this point in time, we do not have any strict guidelines for size of pictures. However, since we do have many members on dial-up services we ask that everyone be considerate of the size of the photos you use in your signature. We suggest that an image not be more than 12K."