Zazzle help

So Groupon is having a deal on Zazzle invites. I am trying to go as cheap as possible with our rehearsal dinner invites and was thinking of using this. It says you can upload a picture to the invite...does that mean I can buy a pdf from etsy with our invitation and print it out through them? I've never done this before so I'm lost lol. Thanks!

http://www.groupon.com/deals/zazzle-21-long-island