Scott M. Fischer has contributed over ninety pieces of Magic card art since Mirage. You can see his work on such cards as Warping Wurm, Culling the Weak, Goblin Welder, the cycle of Runes of Protection, Cowardice, Rakavolver, Gurzigost, Puppeteer, Awe Strike, and Pristine Angel, among many others.
The first step of the creation of a card's art is its art description. The art description tells the artist what the card will do, what its flavor is, and what the mood of the illustration should be. Here were the instructions given to Scott for Time Stop (called "Time Fracture" during playtest):
Color: This is a blue spell card.
Location: This can be an abstract piece.
Action: This spell stops and shatters time for a moment. Show a human wizard (aligned with the color of your choice) midway through casting a spell. But there's a jagged line of sorts in the illustration, and on one side of the line, the wizard is young and the background is lush. On the other side of the divide, the wizard is older (not ancient), and the background is duller.
Notes: This stops a spell from being cast by "rewinding" time.
Next the artist submits one or more sketches with his vision of the art description.
Here's Mr. Fischer's initial sketch submitted for Time Stop. Note how he indicates where to crop the image for the purposes of the Magic card:
Scott took an inspired direction in this sketch. Instead of showing a wizard getting his spell countered by a time rift, he uses imagery to suggest time manipulation in the abstract. The bird and the egg represent the flow of time running backwards, and the gears in the background suggest the internal workings of a clock.
The art team wanted to make sure that the piece didn't emphasize the gears too much: this isn't Mirrodin block anymore, and so technology should be minimized. So they're much more subtle in the final art than in the sketch. Also, you'll see Scott added a blue design in the foreground (that is mimicked in the mage's earrings); it is a pattern of circling swans getting smaller and smaller. That's another representation of the passage of time; the idea for the design came from the hand guard of an antique samurai sword.
And here's how you'll see the card in its final state, in booster packs of Champions of Kamigawa. Get ready to end some turns (with a little help from Scott Fischer) at the prerelease!