Reduced access permissions for cloud providers
The level of permission that your application requests for services like Dropbox is overly broad in nature. This makes it unusable for me as an integration.
If you could update your integration to Dropbox and request a single folder...
"App folder – Access to a single folder created specifically for your app."
... then I could move whatever photos I want into that folder.
Just as a heads up, by taking on such a permissive integration model, you're opening yourself up to a much bigger security risk.
I actually have the same problem on my android phone. Whenever I go to select a photo, the app gathers up all my saved musics album art, making finding the actual picture gallery a real pain!