Details in the sticky thread at the top of the pictures section:
https://www.ninjette.org/forums/showthread.php?t=5611
No essential limit to the number of pics / albums a user can create; have never had to raise the limit (but would if it became necessary). Pics are resized to a moderate size for web viewing, so they don't take a huge amount of space no matter how many there are. Set up an album, load as many pics as you want, add another album or albums if you want, repeat as necessary.
This forum software is pretty dated, so this is a little clunky. The newer xenforo boards I've set up do scrape the pictures no matter how they are loaded, and re-host them on the server itself. Makes for no "where did the pictures go?" threads over the long-term.