Painting

Paintings in Minecraft are simple, low-resolution versions of a canvas; they currently appear in Beta, Alpha, Infdev, and Indev. Most of the twenty five (19 in indev and infdev) current canvases are by Kristoffer Zetterstrand and are shrunken to a low resolution to fit Minecraft's graphical theme. Five more are edits or new paintings. A random image from among these is chosen each time a painting is placed. Paintings currently are not flammable and protect covered flammable blocks from being lit.

Paintings can only be placed on flat, vertical surfaces. An easy way to get a painting to fill up the area you want is to mark the bounds with any solid block and place it in the bottom-left corner. It expands canvas size to the top-right to fill up the wall the best it can. Going up and right one block increases the chance for paintings 4x2 or bigger, though it may still take a few tries to get a large painting.

If hit with a throw-able item (such as an Egg, a Snowball or an Arrow), the painting will drop from the wall and can be picked up and placed again. Arrows will disappear when they hit a painting. Lightning will also knock down paintings.

Crafting
Paintings can be crafted with any color of wool. The color of Wool used does not have an influence of the picture chosen when the painting is placed.

As of Beta 1.2, paintings will drop when any supporting block is removed, making the creation of "Secret Doors" more difficult. You can still attach a larger painting to a block beside a door, and it will cover the door, making it hidden. Note that ladders, signs, and pressure plates technically count as full blocks, but only signs, doors, and pressure plates can be used to aid in the creation of secret passages. Also, trying to open a door behind a painting may knock the painting off the wall.

Paintings may additionally be used to hide chests in walls, as the painting will not prevent a player from opening the chest. This is especially useful on large multi-player servers.

Paintings are not technically a block, and thus can simultaneously exist with water and torches in the same space as itself. An example of this is: place a torch on the wall, place a painting on the same block of the wall by clicking on the wall (not the torch). If the painting is 1x1, it cannot be removed without first removing the torch. Larger paintings on walls covered with torches can still be removed by left clicking. Players and mobs are able to walk through paintings, and light shows through paintings as well.

Canvases
There currently are 25 paintings in Beta. These are mostly based on paintings by Kristoffer Zetterstrand, who also created the Minecraft versions.

Bugs

 * It is possible to get two paintings from destroying one painting.
 * A painting placed over a light source (like a Jack-O-Lantern) will allow the painting to act as a lamp-shade, lighting the room.
 * A painting can have a sign or another painting placed in the same block space (but on a different face), this is because a painting is an entity, so it technically does not take up the block it is in.
 * Paintings do not use the new Smooth Lighting option. When using Smooth Lighting, the painting will use the old lighting, despite the blocks around it.
 * If you have your back against a painting and you fire an arrow that painting will come off of the wall and the arrow is destroyed. An arrow is also destroyed when you fire it at a painting normally.
 * If you place a fence on a block, then put a painting on the block, it will sometimes select a 1x2 painting. This painting can not be removed without removing the block or fence. A way around this is to place the painting before the fence.
 * If a painting is placed in The Nether, standing directly faced towards a painting within reachable distance may sometimes make the inventory's hotbar look more white.
 * You can break paintings in spawn-protected regions in multiplayer.
 * If you place a glass block (or presumably any other block where torches can not be placed) so it forms a corner in front of the painting's edge, then attempt to place a torch on the side of the glass block facing the painting, the torch will be placed on the painting.
 * When sleeping in your bed, right clicking the screen with a painting in your hands will throw the painting.
 * There is a bug that allows you to place a torch on a painting if you hold down the right mouse button and roll across the painting. Alternativley, paintings can be placed over torches.

Trivia

 * To hide a secret room, placing a painting over a open area prevents the doorway from showing, though can still be walked through.
 * Notch recently stated that custom paintings could feature in a future update.
 * Some paintings are rarer than other ones.
 * Some reports indicate that if a creeper explosion destroys walls with paintings on them, the paintings will fall off the walls and are able to be retrieved.
 * They used to be indestructible in SMP, only dropping "fake" paintings every hit, which could not be destroyed or picked up. This was fixed in Beta 1.2.
 * When a painting was placed it sometimes showed a four by four area of solid purple with darker purple between each block. This was because Notch forgot to update the painting texture for the Beta 1.2_01 build, when he added a new painting . This was fixed in Beta 1.3.