The forums use HTML, and not bbCode tags (save for the quote tag). There's a guide next to the text box when you go to post.
That said, I can see images in your sig, so you seem to have it sorted out. Although the example in your post just seems to give a broken image box.
____________"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."
Only fools and children dream of heroes.