It WON'T draw images for you. You should tell with your code how and where to draw them.
Your code simply adds file names into a Listbox, that's all. You have to code where and how do you want your images to be drawn.
As I already said, if you want ICONS then use ExtractAssociatedIcon method to extract icons and then turn on the OwnerDraw property and draw each listbox element yourself.
If you want to draw actual images (jpgs, etc) you will have to LOAD these images from disk into an IMAGE object and then DRAW them somewhere.