Skin

''This page is on the mechanics of skins. For usable uploaded skin textures and the like, see Skins (Gallery).'' Skin refers to the texture that is placed onto a Minecraft person. If one has pre-purchased Minecraft, they can create a skin which will replace the default character texture on their account. This is done with a PNG file the user can upload on the Preferences page. Like many textures, the skin texture is jumbled and distorted looking to save space. A skin will only allow solid color on the skin; no transparancy can be put anywhere but on the second head layer. By default, the second head layer will not show up. If there is a block of transparancy not on any of the texture sensitive areas of the PNG you upload, the second head layer will become visible. This allows the character to have glasses, caps or anything else you can think of (even a bigger head).

It is also possible to preview your custom skin and edit your skin with the Minecraft Skin Editor.



World Textures
A skin can also refer to textures not for the player, such as block textures, item sprites, mob skins etc. Modifying these requires hacking your copy of minecraft.jar. One such example of the environment being skinned is the sun, in this video.