Study the 2 pictures carefully, because they're not
exactly the same. Hunt for the differences, and touch
the spots on either photo.

Locate all 5 differences and move to the next photo. 
Use a "hint" if you're unable to find a difference, but
save hints as long as possible. They score bonus points
for every picture that they're not used to solve.

Speed counts, so play quickly to earn extra photos.