[nailer]

I just did this and the UI is weird and confusing - it looks like I need to statically pick photos in the settings app, which obviously won’t work for day to day use every time I take a photo and want to publish it to instagram.

Not saying it doesn’t work like you say, just saying it doesn’t look like it does.

[bombcar]

At least for Telegram each time you go to pick a photo to share, it offers you the chance to "add more photos visible" or you can click Manage.

I assume Instagram and friends would do the same.

I often just take the photo via Telegram instead, which automatically adds it to your photo roll and gives Telegram access to it. It works relatively well.

[snowwrestler]

You can just hit “done” in the settings app and it will close (with no photos selected).

Then on Instagram (for example) when you go to post, you’ll get a message like “you’ve only let Instagram have partial access to your photos - Manage”. Tapping Manage will let you select photos that Instagram can access.