If you are running out of free space from Google (15 GB) across Google Mail (Gmail), Google Drive, and Google Photos, you can try checking to see if you can compress any original quality images to high quality instead. This offers unlimited storage in high quality size.
To do so, go to the following URL:
https://photos.google.com/settings
Click Recover Storage.
Depending on the number of photos you have, it may take a couple of hours for your new available storage to be updated.
