Sorry - I missed this very valid question.
Unfortunately, in the main, it's a question of, as you say, opening a collection and having a look. However, Alan Jeffries and company have put in a good deal of hard work into providing a brief description of all the BCRA, Myers, and Pills volumes and images, and I have developed a mechanism for listing these. This is very much work in progress, as I have as yet just been provided with the metadata for a couple of volumes.
Here is an example. You will that there is a button to list the individual photographs. It's not a perfect solution, bur one where the creation can be automated for the 200+ volumes.
