The image you see displayed on G+ is not the original image. So what if you can save it directly with no metadata. Even if there was metadata all you have to do is download the image, (which is the original image and contains all the metadata) and strip it out.
Olli is right, in that images can easily be stripped of metadata. However I think it does show the problems of how any created material is treated on the internet. I was involved in a "heated" debate at mu-43 regarding proposed US legislation, and its certainly not my intention to start that up again here, but there are real issues as to what publishing anything on the internet means.
Anything we write, any photographs, video and music we post are just sitting there, and its almost impossible to protect against uses of that material that we might not like, or indeed to track down such use. The notion of getting it removed or god forbid, getting some financial reward for what we create, is also usually out of the question.
For example, I know normally quite reputable web designers, who seem to see nothing wrong in just grabbing images from flickr or other sources on the net and using them without credits or of course a fee. The irony of course is that should anyone copy THEIR designs they suddenly get very angry.
What do we do? Well I have no particular answer other than my gut reaction, which usually involves something painful happening to the body parts of people who steal my work!! and there is certainly a role for legislation of some kind, though just how successful that might be, is something I have doubts about.
Currently, probably all that we can do is make it very clear that our work is NOT free to use and hope for the best. When I post anything on Google+, I do it via a link to my blog and immediately under that link is my copyright assertion statement. This doesn't of course mean that anyone who wants to steal it will be in any way deterred, but at least if I, or the pictures libraries who sell my work get wind of it being used without permission, we have some evidence that it has been clearly stated that respect of copyright is expected.
Finally however, I would say, that companies like Google and Flickr could show that they at least subscribe to the notion that peoples creative work is entitled to be respected, which they and many other internet sites currently don't.