Change to photo/icloud in ios11 kills my data plan

Apparently it is a new behaviour in ios 11.

I am an icloud photo library user.

Prior to ios 11, when I take a photo with my iphone and I happen to be on a mobile network, iphone will not upload my photo right away to icloud. It will clearly indicate the upload is paused to preserve the mobile data. (It will also pause if the iphone is low on battery)

Now in ios11, iphone will upload photo regardless you are on a mobile network or wifi. Imagine my shock I've burnt 1gb of data of my phone plan in a day!

The pause button is so tiny in photo app it is difficult to hit it right.

Now I have one more thing to worry and difficult to control EVERYTIME i take a photo.

Why Apple has to make this change? Why there is no option to control this behaviour? A 4K video can be huge and such kind of upload can easily turn up all the mobile data allowance in a mobile plan.