I don't have my old PC.the hard disk is off?Can I extract the fotos from my old back up???

I have a iphone4 ios 4.2.1 and it is jailbroken, if that makes any difference with my problem. I've transferred some photos from my old computer to my phone but when i synchronized it with my new one, i lost all of them but not the ones i shoot with my phone's cam! I didn't change the...