|interesting you asked that today -- just a couple of days ago, I had a discussion with a friend's wife about just that exact topic. She was raggin' on a sculpture that appeared to be some industrial scrap welded together, and she said "that's not art", to which I took umbrage. (how's that for a $5 word?)
Anyway, I said that my definition of art is anything that is done on *on purpose* specifically to ellicit an *emotional response* when the thing is experienced. A photo, drawing or painting is experienced by viewing. A piece of music is experienced by listening -- you get it...
So, the conversation continues and we agree that, under this definition, there can be no such thing as "good art or bad art" only "pleasing-to-me art" or "not-pleasing-to-me art'. In other words, that it IS art is accepted from the beginning, and the only thing open for discussion is how the piece of art relates to one's own perception and experience with the artwork.
Here's where the conversation got freaky: if you really take that definition to the extreme, you can say that acts of terrorism are politically-motivated art. I totally don't agree with that interpretation, so don't phlame me -- it's just an interesting interpretation.
Anyway, the comment about "advertising" should be taken as a compliment -- advertising is designed to appeal to as many people as possible! Just because your shot might not be all blurry and taken from a funny angle doesn't mean it's not art.