Hi everyone. I just upgraded from the 4s to the 5s, and so I now have LTE. Being pretty excited about this, I had wifi on my phone disabled for awhile even while at home where I would normally use wifi. When I had occasion to go to my Macbook to access some photos I had taken on the phone, I noticed that the photos had not appeared in my photo stream. After some initial consternation, when I looked more closely at the Photo Stream settings on the phone, I realized that photos are only uploaded to my Photo Stream when the phone is on wifi. So, just in case anyone else has had a moment of panic: photos in your camera roll don't automatically get uploaded into your Photo Stream when connected via LTE, but only when connected via wifi. Hope this helps someone!
-Pete
-Pete