[cocktailpeanuts]

Before iOS10, you could press the little camera button from the messages app and a camera would just launch. You take the pic, and send.

Now all you get is this tiny preview rectangle at the bottom. It doesn't launch a full camera so is useless for most cases. That's why I have to open the "real" camera app and take the picture and come back.

[pwinnski]

Next to the "tiny preview rectangle," there's a gray arrow indicator that suggests swiping right. If you do that, you'll find a button you can tap for the old functionality.

So now it's tap-swipe-tap instead of just tap, but in exchange the old functionality of sending an existing photo has changed from a long series of actions to just tap-tap-send.