Can I restore lost photos fron backup? I have an iPhone 4,16G. 

I had a ringtone issue and Apple support did a software reboot. 

Before starting, a phone backup was done. All apps are back as well as phone contacts. However, all my photos are missing. 

Can these be restored?
Photos and Videos in the camera roll (not photo stream) are indeed in the backup file. I would copy the backup file to a second location so that you can have a backup of it. There are also tools that allow you to examine the contents of a iPhone backup. http://addpod.com/juicephone

Try juicephone first and if need be you can restore your phone to the backup temporarily.