how do people get those pictures, or borders around their comments every time they post?

If you mean the item images the code is [item=ITEM NAME HERE] Minus the stars.

For the images in siginature and foum set, go to preferences in the personal part on side bar, and change your forum options to add or change forum set or siggy

Locking.

Please refer to this thread here for ForumText and Signature FAQs :)