Disabling photo/video share in iCloud

Hey all,

Just got back from holiday with nasty bill on my wife's phone. Took us a while to figure out what had happened but we believe it is a case of all the videos and photo's I took on holiday were downloaded to my wife's phone whilst we were abroad.

I'm not sure if she or I turned on the sharing service but we both have relatively new phones so it may just be the default position. But can we do the following:

1. Stop automatically uploading to iCloud
2. Stop automatically downloading from iCloud
3. Specify which pictures/videos to up/dowload from iCLoud.

Thanks in advance.

Lee