Minecraft wiki entry for Painting, associated text: The first image of paintings released by Notch.
The original screenshot behind the "Skull on Fire" painting.
A render of the Burning skull painting that Kristoffer Zetterstrand used as a reference image.
The original "Skull on Fire" painting being painted.
The "Burning Skull" painting as it appeared between versions Beta 1.2_01 and Beta 1.2_02, prior to its texture being added in Beta 1.3.