While on Google Photos click Upload, (probably upper right corner), then click “Google Drive”. If for some reason that didn’t work, just read this short official Google help made to answer this exact question, it will tell you what’s wrong.
If after clicking upload “google drive” doesn’t show up, It’s probably because your account is work/school. One workaround is to share the photos to a non-educational account, and follow the method given at the beginning of this answer.
- Login to Google Drive
- Click on the Settings button ()
- Select Settings
- Make sure Create a Google Photos folder — Automatically put your Google Photos into a folder in My Drive is checked.
- Find and select the image you want to move.
- Click on the Actions button (), and click on Move To…
- Select Google Photos
- Click on the button.
- Your photo has now been moved from Google Drive to Google Photos
Side note: If you want to go the opposite direction (Photos → Drive), then login to Drive, select Google Photos on the left side, select the picture(s) you want to move, click the action button → move, and select the Drive folder to move to.
The only way I found, which is super stupid and as anti-user-friendly as they go (I guess that’s the new Google), is to
- download the files (it will take a while, will create a big ZIP file and might crash the Google Drive app)
- unzip them, because while Google Drive gives you zip, Google Photos doesn’t allow ZIP (output of an app is not accepted in basically the same app, awesome)
- upload to Google Photos, hope that it will actually upload and not crash in the middle
- then you will end up with the photos in both places, so you will need to delete one so it doesn’t count twice to your quota
Not a good user experience. But maybe there is a better way?