Make it more clear that the photos can be clicked to enlarge

## Problem

The photo thumbnails are links to the full-size image, but that is not obvious.

## Proposal

Probably just a note at the top of the page would be sufficient.

Locate the page that renders the photo thumbnails and inspect how those thumbnails link to full-size images. Add a clear note near the top explaining that photos can be clicked to enlarge, then verify the note is visible and the existing links still open the full-size images.

Written by the indexing model from the issue text.