Changing button images - how easy?

I have been looking through the 1.x threads in prep for purchasing 2.x and figured I would start practicing customizing the beta. Not!

I got the Add to Cart button down, but how the heck do I create a button from scratch, like the Add to Wish List which starts out as text???

Being a coding rookie, I figured I would just copy/paste the “Add to Cart” code into the Wish list files and WHAM have a nice little Wish list button - nope. No matter what I do I cannot get the text to change to a button image.

Any suggestions?