John, Impressionism is something you do with a paintbrush. Attempts to do impressionism with a camera don't look ethereal; they look manipulated. I'd bet the original, before the "impressionism" was a nice snapshot of a field of dandelions. Nothing wrong with that.
I guess I would beg to differ. William Neil was just presented on this site. You can do this kind of photography (techniques really) in camera or in post processing, or a combination of the two. But it is as legitimate as any other kind of photography. The same can be accomplished in camera with multiple exposures. And sometimes I do this and sometimes I use both methods. We did this all the time when shooting slide film. PP is just another tool. I already gave one photo site reference to other people, but there are many more photographers that employ this technique. Of course, if you create an image that does not quite work, then one can say you were not successful. The orignal photo, what does that matter?