What you will need:

1. Dinosaur stickers
2. Glue & scissors
3. Green, yellow and blue papers for the background.
4. crayons

Basically, make any background – use some blue clouds or yellow green foliage or trees.
Then leave your toddler to remove the stickers and place them anywhere they like.
Give it a nice title and there you are done with it.

Tip
You can use the same idea with any different stickers. For eg. If you have animal stickers, you can try to make the background like a jungle and let your child just stick the pictures anywhere – with a lil guidance from you of course : )