iCloud Photos and iCloud Backup are two different things.
iCloud Photos are updated dynamically as you add, delete or edit photos.
iCloud Backup only happens periodically when a backup is run manually or automatically.
You can view the contents of iCloud Photos at www.icloud.com
You cannot view the contents of an iCloud Backup; you can only use the backup to do a restore or to setup a device.
iCloud Photos can sync with your other devices automatically.
iCloud Backup does not sync with other devices.
If iCloud Photos is turned on, then the photos aren't also included in iCloud Backups.
Also see: Set up and use iCloud Photos - Apple Support
and What does iCloud back up? - Apple Support
Your screenshot shows that iCloud Photos is still updating. It can take days for 160GB of photos to do the initial upload to iCloud Photos.
If you have older iCloud Backups from before you turned on iCloud Photos, those photos would be included in the previous backups. I'm not sure if iCloud Photos has the ability to delete those photos or move them from Backup to iCloud Photos. You may want to contact Apple Support to see, as it may be that the old Backups are taking up so much space that they will prevent iCloud Photos from completing.