Replied to a thread by @helenhousandi @daljo628 @topher1kenobe @elibud (Twitter)

Tell me what you dream of seeing in WordPress, whether your jokes or your most serious hopes, I'm not making product decisions so this doesn't constitute a promise, I just want to hear about it and get my brain back into that mode again :)
— Helen 侯-Sandí (@helenhousandi) September 8, 2020

This is sort of tangental, but I'd love a form of the mobile app that acted exactly like Instagram, but posted to a WordPress blog.
— topher1kenobe (@topher1kenobe) September 9, 2020

Pretty much. Maybe category. I've always imagined a single pic, rather than many. So I take the pic, put in title, optional desc, optional category, and hit send. If you want to get fancy you could use a Setting to use a custom post type instead of Post, but that's gravy.
— topher1kenobe (@topher1kenobe) September 9, 2020

This is a great use case for Micropub clients and there are a few that will do this already. Try the Micropub plugin along with Quill: for a minimal UI photo post using note (it should default to use the last photo you took too.)

For more details look at Micropub and WordPress: Custom Posting Applications. It uses the W3C Micropub recommended spec and most of the current clients are open source if anyone wants to build their own web or mobile interfaces.

Sunlit for iOS is a Micropub compatible app that supports photos. PhotoPostr looks promising too for photos and collections.

If you want to go crazy to support some of the other niceties on your site, add Simple Location plugin for showing GPS location and weather conditions and Post Kinds plugin for custom (and customizable) photo display (meant to be compatible with Micropub, but doesn’t have Gutenberg support).

Here’s an example photo from this morning:
Naturally it’d be awesome to see Micropub support in core.