can I look at photos that are backed up to icloud?

No. Not if the photos are actually in the backup. If you use iCloud Photos, yes you can look at the photos in iCloud. However, those photos should also be on your device negating the need to see them in iCloud.

iCloud Photos keeps all your photos and your edits in sync across devices and whatever you do on one device is reflected on all devices. If you delete a photo on one device, you delete it everywhere.

If you don’t use iCloud Photos, but you backup with iCloud, your camera roll photos are in the backup but like everything else in the backup, can only be seen by restoring the backup.

You’re quite welcome.