Earlier quoted context omitted.
In case folks don’t know this: on an iPhone you do not need to give an app access to all your photos in order to use photos in the app. Under Privacy > Photos, you can set “Selected Photos” instead of “All Photos” on a per-app basis. Then when you go to add a photo to the app, you first go through an iOS prompt to select the photos the app will have access to. Only then do you go through the app’s photo selection dia…
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.
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.