Create a comment field for each image in a lightbox where a photo editor could enter a note or provide guidance as to a photo's usage. For instance, an editor might say "best image" or "check with reporter for ID" or "use small" or whatever. This comment field would only relate to the image in the context of a specific lightbox; if the same image was used in a different lightbox, it would have a different, lightbox-specific comment field.