New submitter Adekyn
writes that, according to David A. Arnott of The Business Journals, the Google Photos app will sync your photos — even after you have deleted the application from your device
From the article: All I had to do to turn my phone into a stealth Google Photos uploader was to turn on the backup sync, then uninstall the app. Whereas one might reasonably believe uninstalling the app from the phone would stop photos from uploading automatically to Google Photos, the device still does it even in the app’s absence. Since making this discovery, I have re-created the issue multiple times in multiple settings on my Galaxy S5.
I reached out to Google, and after reaching someone on the phone and describing the issue, was told to wait for a comment. Several hours later, I received a terse email that said, “The backup was as intended.” If I want to stop it from happening, I was told I'd have to change settings in Google Play Services.
A video of the process accompanies the article.