I had no idea that the picture was so huge! It's probably the largest picture I've ever had to tell the differences between. You would think this would just be something for kids. It's very difficult! Are these real photographs? If so, I'm glad you used them.
Many of them are easy to spot. It's just that I don't think I have enough time. It seems to be too big a picture. Yes, I know I sound whiney, but a lot of other ones are much easier. At least this is something different for you guys.
Nice! More levels and maybe a soundtrack while looking for differences would be appreciated! :)