I want to be able to pick an image and fill the label completely with the image

Add Image?

Choose Background??

I want to pick an image and fill the entire label with it.. not just a small picture

You need to spend some quality time in the Help Files and experiment a little.

Add Image – resize it to suite you needs.

Now you can't make a square picture fit into a round disc perfectly or a rectangular picture onto a square Front/Back CD case but play with it.