That'd be the Swedish artist who calls himself "Junkboy". You may remember him from such JPEGs and GIFs as this Portal and Ico mash-up or these 22 spectacular "dem akes" of modern and classic games. The accomplished pixel and digital paint artist is now one of the full-time staffers making Minecraft better and prettier.
To see more of Junkboy's work, hit his deviantArt account and start fantasising about how much better Creeper's will look when Minecraft makes its way out of alpha.
Survival Mode Multiplayer is priority #1 [Minecraft - Thanks Jonathan!]