I'm sorry about the issue. What's the model of your phone?
Is this Google Photos Auto Backup?
Can you please open the app called Photos, then go to menu (usually, tap on the 3-bar icon at the upper left corner), then tap on the option Back up & sync, then turn it Off.
, next, open the Settings app icon, then go to Applications -> Application manager, then go to the All tab (swipe from right to left until you see the All option), then scroll down, then tap on the item Gallery, then Clear data and confirm, then check.
Only if needed, sign in your google / gmail account at the website below, and delete any photos you want there:
Please reply back to continue troubleshooting. Thank you.