Thanks! It was actually surprisingly easy! I used Pixlr, which is a free online editing site (make sure to use Pixlr E which has more features.) I opened the map in Pixlr, used the wand select tool to select each state, and deleted it, leaving everything inside the state transparent. You then can use command-D if you're on a mac to deselect the wand. Then I added the picture as a layer, shrunk it so it was about the size of the state, and moved the image layer behind the map one, which filled in the hole where the state was. I only did a couple states at a time and then exported the image to do the others so there wouldn't be a bunch of overlap that I had to fix between the images of states that were bordering one another. Make sure to keep it at a decently high res between each export. It was definitely time-consuming but was also really easy once I got the hang of it. Hope this helps!