Word of advice: Don't use iFile (or any other means) to mess with your camera roll, music, videos, etc. You can find all these items buried in directories in your file system, but what you may not know is that they are also all tracked in iPhone databases. If you add, move, or delete anything, it will cause weird problems. I tried adding a photo to my camera roll using iFile, but after that any photos taken with the phone didn't show up in the roll.
To clear this up, I had to move all my camera roll items to my PC and wipe the phone of all photos (plus manually delete the photo database). But now I don't have any of my previously shot videos on my phone (which iTunes won't let you sync back).
So even on a Jailbroken iPhone, there are certain things you don't want to mess with outside of iTunes sync.