this idea on Pinterest I immediately was inspired to create something similar as a fun Valentine's Day card for them from my girls.
If you have a puzzle your kids have outgrown, like we did, then you don't have to buy anything and makes this a great recycling project. Otherwise you can find blank puzzles at the craft store.
Start by painting all the puzzle pieces. We used an old 24-piece puzzle. We didn't paint the puzzle as a whole (put together) because I was afraid of the pieces sticking together.