Terrain.png



terrain.png was an image file found inside minecraft.jar that was used to load the game's textures.

Format
terrain.png is a fixed-width 256×256-pixel file that is split into different 16×16 squares which correspond to the texture of each block found in-game. Unused sections of the texture are colored magenta, similar to the missing texture block found in later versions.

Usage
Before the introduction of texture packs, terrain.png had to be edited in order to change any textures found in-game. The file would have to be placed inside an edited minecraft.jar file in order to work.

If a block attempted to use textures from the unused, magenta-colored parts of the file, the block would be colored magenta:. Examples of vanilla blocks that drew from such parts of the texture at one point or another are the locked chest, several extreme values of wheat, and an overeaten cake iteration.