There is a “Accepts NSFW” option on a profile, with “Alway” “Never” and “Not at First” as options but these are purely performative - nobody reads profiles or cares in the slightest.

Tinder has a feature where when you use an explicit word in a chat, it will ask “are you sure, this user may find this offensive” before you hit send.

Similarly, if a recipient has “Never” marked for NSFW pics, there should be a warning to someone sending that the person may not receive it well, or they may not get a response, etc. Or the pics should be blurred, or there should be an option to ask the user if they’d accept rhe NSFW pics.

Basically, find a way to make the “Never” function useful so the app isn’t just drowning in dick and asshole pics.