I previously used a program that created picture galleries the I could host on my NAS, and am looking at Piwigo for some much added capability.  I was surprised that there does not seem to be a way to make a newly registered user remain a guest until authenticated.  Or is there and I'm missing it?

I know I can make all the galleries private and use groups to give users permission to view them.  But I like the idea of letting guests (and newly registered, unauthenticated users) be able to see some lower resolution pictures but not add comments.

Piwigo version: 2.7.4