How to Back Up My Photos on High Quality on Google Photos? [Solved]

Photos backed up in High Quality in Google Photos do not count against your Google Drive space. Your remaining should not change at all.

Only photos backed up in “Original” are count against your Google Drive space as if you backed them up to Google Drive directly.

Actually, if you choose the High Quality option, they don’t count against your Google Drive storage space. They only count against it if you choose the Original Size option:

Choose a storage size

They count against your google drive space because Google on only allows pictures below a certain resolution to not take up google drive storage, if your pictures are a higher resolution than that, the pictures will take up space.