Just a warning though: I made something similar a few years ago (actually recovered existing coasters) and although they were very pretty, the Modge Podge did not go well with hot cups of coffee, LOL!
I did something similar to this a couple years ago. I printed pictures on tissue paper and then modge podged them to the coasters. The person I gave them to says they are still in good condition, however he's not a coffee person, so most likely just puts cold drinks on them.