Finally, let's get away for guessing about what Apple might be doing. It was easy enough to search "iOS open in" to find this support to support this feature and it had been around a few years. There's no reason to suggest that Apple is copying Android on this feature.
2. Why does iMessage offer so many options to open a picture in? And why are apps that don't share photos included in this list?
3. Why can't iMessage share photos to iCloud?
4. Is iMessage broken? What makes iMessage different from other Apple apps included in iOS?
5. Why isn't Apple leading the charge and actively pushing this much needed interaction?
I think Android's approach is much better, which is why I was so excited at the possibility that Apple might be working on something similar. Alas...
And I did search and found nothing related to what's going on within iMessage, which I found odd. Nothing wrong with trying to guess what a company is doing.
This is one of the reasons that I find Android far more useful for most workflows than iOS. I was amazed that Twitter and Facebook integration had to be built in manually.
Apple seems to be experimenting with native inter-app sharing on iOS 7 within the iMessage app. If you try to share an image you’ve received through iMessage you’ll notice a much larger selection of sharing options than normally available on other iOS apps.
You can also do quite a lot with URL Schemes but more apps need to implement support and publish their requirements.
There is also the X-URL-Callback spec which could be implemented by more apps. Google is using this spec on iOS.
http://x-callback-url.com/specifications/
https://developers.google.com/chrome/mobile/docs/ios-links
https://developer.apple.com/library/ios/documentation/uikit/...
Finally, let's get away for guessing about what Apple might be doing. It was easy enough to search "iOS open in" to find this support to support this feature and it had been around a few years. There's no reason to suggest that Apple is copying Android on this feature.