how do i find my icloud back up photos ??

If you have iCloud photos turned on, they are not part of a backup. Photos is synced from iCloud to your device. If you wish to view photos in iCloud, you use a computer browser to log into www.icloud.com and then click on the Photos icon. If not using iCloud photos, then photos would be in your backup and the only way to see them is to restore your device to your backup. You cannot view individual data in an iPhone backup.