I wondered the same thing. On my phone 32g, I didn't have that problem. My wifes phone 16g not a problem, on my moms 8g we had to delete pics and some video to get the space. I think that maybe it is because of a bug in the system and it could be resolved soon. If you don't already do this, make a backup, delete all the pics off camera roll (only if they are in photo stream) that frees up lots of space, delete any apps you don't need, and that should help.