Pop Art Graffiti
Graffiti is images or words made on public surfaces such as brick walls. Graffiti is the defacement of a surface using spray paint, markers, or other utensils. If graffiti is done without the property owner’s permission it can be considered vandalism, which is against the law in most countries. Graffiti has been around for centuries, and has begun to grow into what is now known as “modern graffiti”. Graffiti is often used as an advertisement, and is also commonly used to spread social and political messages. Graffiti has also become a modern art form and is featured in galleries world wide. A very famous artist, Jean-Michel Basquiat, started his career with graffiti. He was a friend of Andy Warhol, a famous pop artist, and his pieces sell for high prices still today.
Below are a few examples of today’s graffiti.

The image above is an image of a mushroom, made on a brick wall in Barcelona.

This shot was taken in a very famous street in Duesseldorf, Germany with a lot of graffiti art.
Graffiti by Jean-Michel Basquiat.

Check out this link. It fits your website.
http://www.youtube.com/watch?v=nUDIoN-_Hxs