Looking at the above image you might be tempted to accuse me of Photoshopping it. You can achieve this somewhat impressionistic appearance by selectively using the various "art" filters on Photoshop: indeed I have used them myself on many occasions to brighten up a dull shot. It would appear, however, that you do not need to invest in Photoshop to get the same effect - simply have your camera out of focus and allow your hand to tremble a little when you press the shutter. This was true of the days when cameras had manual focus lenses and shutters that had to be physically set. These days, there is a digital filter for it.
The picture was taken in Paris, during my honeymoon there in 1973 (as good as an excuse for camera shake as I can think of). I have just realised, that is forty years ago : I must make a note to myself in my on-line digital diary to remember my anniversary later this year.