Google Photos new Express backup mode will help users save their data
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Unless you are on Wi-Fi all day, saving your photos with the Google Photos app can eat through your data. The images are saved in full resolution, and if you have a data cap, you might not want to consume so much of your monthly allowance on holding on to these files. But there is help on the way. Google is about to rollout a new feature called Express that will allow Google Photos users to have their cake and eat it too.
The update will also allow users to set a limit on the amount of data that Google Photos can use daily, starting as low as 5MB. Other options are 10MB, 30MB and unlimited. The settings for Express will be found in the "backup settings" of Android flavored devices. Those downloading the app off of the Google Play Store will be able to make their selection while setting up the app.

Express is coming to Google Photos to save your data
Things that are NOT allowed: