If you can still display the pix on your iPhone, they aren't lost ... yet!
iPhones have a nasty habit of deleting stuff when they think they need the space for something else, so get them off the phone and onto the PC. There are (as others have said) several apps to do that.
My iPhone is jailbroken, so it's very easy to move stuff. On a non-jailbroken one it's trickier but possible.