I searched, but did not find anything about this.

I replaced the dock connector on a friends 3G (not jailbroken). He had swapped his SIM to an old phone in the meantime. I was going through and making sure everything worked. I noticed that new pictures were not showing up in the camera roll. While in the camera app, it would show the thumbnail just fine, but when tapping the thumbnail, it would not show the photo in the camera roll. When viewing the photos on my PC via USB, the photos would show up fine. I finally figured out that the new photos were saving to the very beginning of my camera roll???

After searching online for a while for a solution (which I didnt find), I happened to notice the time was wrong. Then it dawned on me. The date/time had reset to default of December 31, 1999. Since I didn't have a SIM card installed, and the date/time setting was set to 'Automatically adjust', the time stayed at default die to lack of cell service. The new photos I was taking had a date of 1999. The camera roll displays photos in date order (most recent "date" at the bottom) so all the pics I was taking went to the top. I manually changed the date and voila, problem solved.

Like I said, I didn't see anything (in this circumstance) useful when I was searching, so I figured I'd post this in hopes that it may help someone in the future.