Know Your Audience:
Shorter is Sometimes Better: We've found that photo montages that are between 8 - 12 minutes in length are ideal. This usually works out to about 3 songs and 75-100 photographs.
Choose Quality Photographs: Photographs that look great printed will also look great while scanned. Photographs that are extremely dark or grainy, while perhaps improved somewhat, will still not appear the best.
Choose a Variety of Photographs: Using a variety of photographs can keep your audience interest.