Minecraft wiki entry for Easter_eggs, associated text: Some of the textures have pixels set to 0 opacity, which makes them appear transparent, when viewed with most image viewers. However, the color information of these pixels is still present, and can be retrieved by disabling the alpha channel. Most of these textures are probably leftovers from the creation of the texture, that the editing program didn't erase but instead simply set the opacity to 0. Textures listed here had their alpha channel disabled to reveal unused/hidden pixels in the texture. Most of the invisible pixels are from development of the texture or already existing texture has been used as a template during development.