You can see all of your iCloud data on your iPad within the apps that are syncing data with iCloud (contacts, calendars, notes, etc.). Any photos you have in iCloud are visibile within the Phtos app, in the my photo stream and shared stream albums. These don't use any of your iCloud storage. The only photos in your iCloud account are camera roll photos included in your iCloud backup. However, you can't see any of the files in the backup; you can only restore the backup to your device.