Apps using the camera API crash after taking a picture on an iPhone 4S running iOS 7
Rebooting always fixes the problem for me.

As for permanent solutions, haven't tried this myself but this comment has a possible solution (pre-iOS 7 however iOS users have reported success):  http://www.iphoneincanada.ca/how-to/how-to-fix-iphone-camera-roll-crash-and-photos-turned-to-other-in-itunes/#comment-347059180