Start small.

An instagram like micro app. Pull in posts from typical photography hastags. Have a dedicated #nostrphotography hastags for all posts from the app.

Looking gorgeous. 

Limit text. 

Photography contests. 

Surface high quality content. 

The usual like, comment, zap, block, follow, NSFW filters etc 

All this might already exist πŸ˜‚πŸ˜‚