Can I get back pictures on my iphone that I accidentally overwrote with a backup?

My wife got a new iPhone 4s today. She took a handful of important photos. When we got home, I pkugged it in and did the nornal restore from last nights backup to make it the same as her old phone. Now all the new pics are gone. Is there ANY way to get them back?

Not unless you did a backup on her photos that you deleted.

Not if she did not back them up or sync them to a cloud service.