Instead of limiting Public Gallery posts by 24 hours from each post, limit it per calendar day. 4 posts from 12am SLT to 12am SLT for example.

As it is now, if I post 4 images to the Public Gallery at 11pm today, I have to wait until 11:01pm the next day before I can post again. If it were limited by day then users wouldn't have to play this waiting game, they could post again in the morning if they liked, but they'd still be limited per day. This would make engaging with the site a lot less frustrating while still preventing snapshot spam.

I'd link it to SLT to keep consistent with SecondLife.