When I plug in my iPhone, iTunes always tries to recover 2 photos. It's only done this since I got my iPhone 4 way back when they came out.
I've had the phone replaced once and it did it again when I plugged in the new one. I've had to reset my phone before, for another reason, and it still does it.
I've Google'd my heart out multiple times and I come up with no solutions or any ideas as to why it's doing this.