Stacks of unsorted photos can get out of control if left unsorted for too long. Here are a few tips for taming these piles.
Set them aside. Remove pictures from the photo-processing envelopes. These envelopes often are not acid-free and over time can damage photos.
Use bought storage. Store them in conventional photo albums or photo-safe boxes and use acid-free, lignin-free index cards to organize photos by subject and date.
Avoid sunlight. Keep your albums and storage boxes out of direct sunlight and away from high humidity areas.
Label them carefully. When writing on the backs of photos use only a soft lead pencil, a grease pencil, or an acid-free permanent marker -- preferably one that writes on slick surfaces, won't bleed through, and dries quickly so you can stack photos immediately.