Once I save my photos to the airport time capsule; can I delete them from the computer drive?

No.. if you do that you will have no backup.

Worse if you are using Time Machine to backup, it will also delete your photos from the backup. So then you will have no photos at all.

If you need to store photos off the internal computer drive use an external drive.. the TC is unsuitable for photo storage. Especially iphoto library .. it will easily be corrupted if you attempt to use it as a live accessible and writable area.

Time Capsule is for your backups, not for your "live" or "working" files.

i thought the airport time capsule was an external drive? Can i not backup to this drive and then delete photo from my hard drive to open up space?

Please think about this for a moment.

If you move your images to the Time Capsule...and delete them from your computer's hard drive......then, the only copy of the images that you will have will be on the Time Capsule.

So, now your "originals" are on the Time Capsule....since you deleted them from the computer's hard drive to create more space.

When...not if....the Time Capsule has a problem and you cannot access your images.......where will your backups of your images be?