The photo picking intent leads to a confusing UI - it's common for phones to have many photo picking intents, so a typical flow would be:

* User clicks "attach photo"

* Phone asks, do you want to use "Photos", "Gallery", "Google Photos", "Camera".

* User wants to share a screenshot - so they don't know which to pick. They choose "Gallery".

* The built in gallery app doesn't show images apart from those taken with the camera. User goes back.

* User picks "Google Photos"

* Google photos only shows screenshots under a confusingly named "device folders" link in a hidden-by-default side menu. User doesn't find that.

* User tries "Photos".

* That turns out to be an alias of Google Photos put there by the phone manufacturer.

* User tries "Camera". That lets them take a picture, or to scroll through another list of past camera photos.

* User gives up.

And we wonder why apps don't use that feature of the platform...