I tend to try and get a few graphics in there first, and then start programming. I'll use a few older assets as placeholders in some cases, but I try to get the final graphics done as quickly as I can.
I think Scott Cawthon put it perfectly; "No I use the real graphics right away, otherwise I can’t get motivated for the project. If I’m not proud of the very first piece of work for a game then I quit or start over weeks later. Every element has to be a finished piece."