Can I use some of your pictures for this new graffiti site I'm building?

No. The point of you doing a new graffiti site is to display original artwork that is not already on the web. If you like my stuff and would like to represent it, feel free to link my site, but please refrain from taking any material off this site. I would consider that stealing, and since all artwork on this site is copyrighted, it may have severe consequences.