I think many people in comments to your post not understand that "can" is not equal to "will". The rights they require are mostly for avoiding issues with some countries, testing, avoiding responsibility during hack attacks, removing duplicates and editing some files that could be browser open.

If anyone thinks that Google, multi billion company would take your photo and publish it to make money out of it - you are creating issues to yourself.

Its Google, they are all about your data, statistics, behaviours and keywords. Not about stealing things and using your photos/artwork for marketing purposes.

Cloud = trust. No matter if its Dropbox or Skydrive or Box. On the end of the day you either trust company or not. No matter what's in TOS.