It's Cherie Blair but is it art?

What is the nature of art? It's a question which intrigues me a lot. I always find it strange that something which can be so readily quantified in terms of value can also be so subjective.

Take this recent portrait (inset) of Cherie Blair for instance. And I mean please take it out of my sight!
Admittedly the artist, Adam Birtwistle, did not have a very appealing subject to start with - Cherie Blair is one of the least attractive women in public life. In fact I think she is even less visually attractive than the Bride of Wildenstein herself.

However Birtwhistle has succedded in making her even uglier with a few splodges of paint and, no doubt several days or weeks of work. And as far as I'm concerned it is still not art.

I created the main picture in a few minutes in Photoshop. I know which I'd rather hang on my wall and which I'd rather pay money for. That said, it still does not make my masterpiece into art by any stretch of the word. So is the definition of art then simply a matter of how much work has been put into its creation?

But suppose Photoshop had never been invented and I had to write the software before I could transform Ms Blair into the masterpiece you see before you. It would have taken me months or even years to achieve and still the end result would not have been art.