Do you have a Photobucket account? If not, you should make one. Here's the link:www.photobucket.com
When you've made the account, you can upload photos etc. from your computer to Photobucket. When you are done doing that, you can get a link code for whatever image you want from Photobucket and put it into your profile in the "Signature" thingy. All you need to do is copy/paste.
I am not a genius with computers but I hope that helps
If not, maybe someone else could explain it to you.