Select a photo and choose fun. Now select Puzzle. It'll cut up your picture into six pieces for you to re-order. Once completed you can have the option to have a 12, 24 or 48 piece puzzle. Now for the secret. Press and hold the "1" button and the 48 piece puzzle changes into a 192 piece puzzle. Have fun.
Here's a bit of fun. The Black Cat that lurks in the yellow bar in the photo channel menus dispenses useful information about the Wii. The only problem is it is a shy cat. So you'll have to be quick to catch it.