This is a terribly small resolution scan, I would contact the provider to see if better could not be acquired. It looks like preview thumbnails rather than actual scans.

Perhaps the actual ones are available and simply not provided properly.

If they are not, but the book is still available, considering the location, one could offer to pay to have it done perhaps cheaply.

Otherwise, to enlarge the photos, one would want to do it in bulk with a batch process, and adjust the gamma, contrast, sharpness, and whatever else might provide a better quality enlargement, but for what it is worth I do not think you will get very far.

A program that would do this, would be Irfanview, I use the portable version. You would choose a batch conversion and set the parameters.

Very nice find!