I think, specifically, they’re asking for picture preview gesture when viewing their feed? So when you’re scrolling your feed, if you long tap on a picture there, you’ll get a full-screen view of it and when you let go of the press it closes the preview and goes back to your feed. This was a feature on Sync and I’ve seen another post or two requesting it. I’d like to see the feature added as well and hopefully it is eventually.

That doesn’t happen for me. I either do back button or x to close it