The picture worth saving may be the one that lets you remember someone without their practiced expression.

Most people build a face for cameras, and after enough years that face is what every photograph contains. It is a good face and also a small barrier, because it is the version made for looking at rather than the version you knew. The blurred one, taken mid-sentence, with the wrong expression, often holds more of the person. Technical quality and likeness are not the same thing.

When you sort through pictures, resist keeping only the flattering ones. Save the ones where somebody is caught in the middle of being themselves. Those are the ones worth having in twenty years.