Check out the first post in the sticky "How to make the search function work for you". In it is a link to LHCF How-To's, including instructions on adding photos. Here's the link:
Also, you can't post signature pics unless they are uploaded to a picture hosting site. You can upload your saved pics to a free image hosting site, like PhotoBucket, and then add them to your siggy. You can't link pics from Fotki, either - that site doesn't allow "hotlinking".