Hi Jimmy,
I love photographs that tell a story, and this one is definitely doing that. Aside from the story the street artist is creating on that large canvas there are also the people walking by, looking at the painting and becoming part of your own scene.
When it comes to manipulating photographs like this, it is worthwhile sticking to what most photojournalists would normally apply to a photograph; in this instance some minor tonal corrections and the removal of the few distracting spots from the picture.
To begin with I used Photoshop's Curves adjustment to brighten the image, shifting the white point closer to the middle and moving the middle of the curve outwards to brighten the midtones.
The next adjustment I made was a rather simple one. I used the Dodge tool in Photoshop to gently brighten the pavement. This helps make the pedestrians stand out against background.
Finally, if you are more interested in aesthetics than creating an accurate record of the scene there are a few spots in the picture – small bits of paper, gum, etc – that you could clone out with the Healing Brush. You will also notice the guy in the dark suit in the bottom of the picture who is wearing a white shoe. It's a distraction and I'd be tempted to get rid of it.
Good work.
Cheers,
Anthony.
Image Doctor's edited version