Add an image to vgui

How would I add an image to a vgui? I saw DImage on gmod wiki, but I don’t know if that needs to be a vtf or what. Can someone please help me?

A DImage can only be used with a vtf, there is a dll that allows you to use image files, it may not be what your looking for though, I think it can only be used if the client has the dll.

http://www.facepunch.com/showthread.php?t=730661