IPhone 4 Transfering Pictures
When, upgrading, I always just backup my old iPhone to iTunes and restore the iTunes backup.  That gets all pics including the camera roll. 

I just recently upgraded from a 5s to 6, and I still have the very first pic I took with an iPhone on July 11, 2008 and that is how I've always done it.  

Note: backup in iTunes is not the same as syncing with iTunes.  Click the phone icon to find the backup button.