This might be a quick functionality win for a relatively small amount of coding...

From an Android perspective...

(a) Make the photos (files) created and managed by the "Photos" section of Drive visible as a special top level sub-folder of the "My Files" area.

(b) In the "My Files" view enable copying/moving between "Photos" and "My Files".

This keeps these actions in the cloud and allows photos uploaded to Drive "My Files" as files (ie, on android, "shared" with Drive from another app), to be later moved to "Photos". No time take downloading, uploading etc.