Here is a picture cube I made which celebrates The Big Lebowski.
I sourced the pictures from the DVD and took them to a printer and got them colour printed at 300dpi and laminated. Then I chopped them up with a knife and glued them on. Very easy. Here is what I learned:
1. I used bostik all-purpose glue which worked well, but I found it was good to have a (new) jay cloth nearby to wipe up any extra glue on the cube pieces.
2. I didn't arrange the pictures so that the gaps between the cubes would fit in properly. That means some of them look a bit strange. Take this in to account if you're making a picture cube for yourself.
3. I cut mine with a decent sharp craft knife, but I found it very difficult because both the laminate and the ruler I was using were quite slippy. That caused a couple of the cuts to go minorly squint. If you have access to a fine-bladed guillotine, that would be best.
4. This is a really easy and fun beginner mod.