How can I recover my photos from apple TV 1st Generation?

It is not meant to be used as stored, there is no easy way to recover

The answer of Vazandrew is a bit short. But correct, all the media stored on your Apple TV come from your Mac via iTunes, that's the source for all the media.

If you happened to have thrown away the source photo's from iPhoto you have to get them back from your backup disk or timecapsule.

If you have no back up ... oops