The creator was Dave McKean, a well known artist most known for his work on The Sandman by Neil Gaiman. It was based off of an earlier work he’d made for a collection of Sandman stories called “Brief Lives”.
Here’s what Mike Portnoy said:
MP: What happened was, we had another artist do the album cover and I just did not like what was delivered – the guy just did not take any of the ideas or the concepts that we had put forward. After being unhappy with the initial cover, we were given a portfolio of different artists that were available and we came across some of Dave’s stuff in there and there was this one image of this old man’s face made up of a million different old fashioned photos, which I thought was perfect. So I went back to the label and said “let’s see if we can commission this photo” and they went back to Dave, and it turns out that it had already been licensed for the Sandman comic book series, but Dave said he was more than willing to create a new piece of art based around the same idea and that’s what happened. Within a few days, he had come up with the new artwork which became the album cover. The funny thing is, I didn’t even know Dave did the Keep It To Yourself cover until afterwards. In fact, I showed the album cover to James after it was done and he didn’t know that Dave was doing it, and he said “wait a minute! This is the same guy that did the Mullmuzzler cover!” and I was like “you’re kidding me – I had no idea!”