Picture cubes are the same as normal 3x3x3 cubes except that the stickers have pictures on them and not plain old colours. There are lots of variations on this theme. The Rubenking, Ultimate Cube, Shepherd's Cube, Maze Cube and many other variations are available. Pictures of card suits and fruits were common in the 1980s and some of these puzzles are making their way back into use through the marketplace created by ebay.
The pictures affect the way that you solve the cube. Pictures can make it harder to spot patterns and you have to take a little more care to make sure things are oriented correctly. The main difference comes at the end when you realise that the centre pieces (which are not sensitive to orientation normally) are all twisted. You will need a few extra algorithms (on the Pillowed Mastermorphix page) to complete the puzzle.
You can buy sticker sets with pictures on these days. If you buy a cube with funny stickers, you are most likely going to get a pretty bad cube. Putting custom stickers on a decent cube makes for a much better puzzle.