Yep, exactly, just looped through each image with the same prompt and stored the results in a SQLite database to search through and maybe present more than a simple WebUI in the future.
If you want to see, here it is:
https://gist.github.com/Q726kbXuN/f300149131c008798411aa3246...
Here's an example of the kind of detail it built up for me for one image:
It's wrapped up in a bunch of POC code around talking to LLMs, so it's very very messy, but it does work. Probably will even work for someone that's not me.