No. Google Photos does not backup photos on iPhone without logging into app. You need to open Google Photos app and keep it active for backup to work on iOS devices. Google Photos backup service allows you to save your iPhone photos and videos to your Google Photos library, including the photos and videos that you capture in the future. But, you need to open the Google Photos app to keep it active.
You have another option to backup your iPhone photos and videos i.e. iCloud. But here, you have to pay for since your photos exceed the 5GB of free storage space.
Automate backup & migration of your photos & videos with support for all top services.
Trusted by users in 125+ countries.
“Your pictures are scattered. PicBackMan helps you bring order to your digital memories.”