Make sure to check the box that says "Use wiki code in signature", or something along those lines. Also the image you're linking to initially is invalid, and the second image is missing a brace at the end (and probably doesn't exist also if they're the same image).
Break down the syntax, kinda like you'd do with a complicated set of math operations: 2*3+6/3*7-93*2+-1 (the answer is -167).
You have this:
Jthemarvelfan, king of all Dwarves
You start and end with image code that you know works. The next bit is a link to your profile, with the link target and then the text to display, separated by a pipe (|). The text to display has span text surrounding it. Instead of the span tags surrounding just the text to display inside the link, move them so they surround the whole link.
Use the source editor, it will make your life easier if you are doing anything. Should be an option in your user preferences for default editor. There might also be a button somewhere to edit the source when you're using the visual editor.