If you are looking for a fun way to turn photos into jigsaw puzzles, Up in Pieces is the app to accomplish this. Once the image is loaded, you are able to choose the type of jigsaw puzzle you would like created. Open up your newly created puzzle and drag the puzzle pieces from the tray to create your picture.
I can see a lot of potential for this in my 1st grade classroom. Each of our Journey's reading lessons via Houghton Mifflin Harcourt introduces students to new words each week. This curriculum even comes with pre-made photo cards of the words that could be downloaded and inserted into this app for students to practice.