Recently I worked on a project where I was just doing front end development and managing the code. This is one of the first times where the designer did not hand off the master files but instead cut images for us devs to use. All in all it slowed things down a lot. When we got to making sprite images, all of the files had to be re-done. We never received images that looked acceptable for IE 6. In fairness to the designer, he was working blind and disconnected from the code.
All in all it could have been easier and now I know how to handle it for the next project.