Were they on a different phone with the google account AND synced to the google account itself? Or just on an old phone that used that account?
If they were just on a different phone, and not in the actual google account, then unless you can get them physically off that old phone, you won't be able to get them.
However, if they are in an actual google account (and not just on another phone).
1. Open the "Google Photos" app .
2. Tap the photo you want to save to your device.
3. Tap the "Options Menu".
4. Tap "Download" (may say "Restore" instead).
5. Repeat for each photo.
NOTE: You can also save all the images from the google photos account to a computer (usually in bulk) while on a computer. Save them to a folder and then connect...