Is there anyway to only keep pics on the cloud drive and not a copy on my computer?
There are two basic ways.
Don't use the Google Drive desktop app. Just upload your files to Google Drive using the web interface.
If you want to be able to sync some files, but not all, you can define which folders under Google Drive should be included/excluded.
Simply right-click the Google Drive app. Check "Only sync some folders to this computer". Then check the folders that you want to sync. Files that are in unchecked folders will not be synced. After that, you can delete your local copies and the files in the cloud will be unaffected.
(To prevent accidentally losing files, I would create the folder in the Google Drive interface first, and leave it empty. Then use the Google Drive app to exclude that folder from syncing. Then upload the photo files to the folder on the web.)