Solution for iCloud Downloading Photos...
Ok... I just had the same issue and after an hour of trying to figure this out... reading threads in forums... and nobody had a reliable solution... I got it...! LOL
Anyway, it's as simple as hooking up your iPhone to your computer and getting into iTunes > go to your iPhone > go to Photos > Put a check in the box for "Sync Photos from". Now make sure you pick your folder that you have previously used for photos. Otherwise, you can do what I did and just said "To heck with it" and created a blank folder with zero pictures in it. Last, just hit "Apply" down at the bottom of iTunes. Voila! Problem solved! No more spinning, no more downloading, no more killing the battery and no more headache!
Essentially, all you're doing is manually RE-SYNCING your photos and overriding the iCloud sync download to your iPhone.
P.S. - If you do as I did with the blank folder with zero photos, your phone's Camera Roll will have 0 photos in it. And if you had seperate Albums that you have created... they will be gone too. So, if you want to make sure to keep all of your photos and albums... MAKE SURE YOU SELECT THOSE FOLDERS THROUGH ITUNES BEFORE YOU HIT "APPLY"!