You are allowed to use SketchBlast.com graphics as long as the following requirements are met:
1. You can not sell or redistribute the files in part or whole on your site, or any stock photography or vector site, including offline or online.
2. You can not use the files for pornography, SPAM, illegal business, crime, alcohol, gambling, racial or sexual websites.
3. You can not host the downloaded source files on your server and redistribute as your own, either in part or whole. If you want to share the files, you can link back to the original source page or location of Psdblast.com.