In your profiles, you are given signature space. Most people usually place a image or some text links in there, however, there are some things you should know on what you can do in this space. You can fit up to 300 characters in your signature space, use it wisely. If you use a image (like most people do), the image must not be no larger than 400 x 150 pixels. You may place multiple images in your signature though, as long as it doesn't go over the limitations (ex: four 100 x 150 images is acceptable). Text is fine of course, as long as they're kept neat and organized and contains no foul language. I also wouldn't advice using big text like this that stretches across the entire page because you think it looks cool and awesome and makes you stand out more. No YouTube videos or music players in signature space.