When you delete pictures on Google Photos, these images are moved into the trash folder and stay there for 60 days to give you ample time to change your mind. But since Google arranges trashed images by the date they were taken, it isn't clear when the 60 days are up. Thankfully, Google has updated the interface, and it now shows a countdown timer that informs you how many days are left until a photo is permanently deleted. You can speed up the process and remove it yourself or restore the image before your time runs out. This feature seems to be limited to the Android app, and it comes with version 4.51 of Google Photos. It's a server-side change, so you don't have to do anything but wait until it rolls out to you.
Source: Android Police