256

What does 256 mean in a Computer?

256 is the total number of unique values you can store in 8 bits. Since 8 bits is 1 byte, it's also the total number of unique values in 1 byte.

Examples

In Images

Some image formats, like PNG and GIF, support storing the colors of the pixels as an indexed palette where the size of the index is 8 bits. This means the maximum number of colors you can have is 256.

In Pixel Art

256 is the total number of colors that a Super Nintendo can display at one time at screen, although it had more than 256 colors to choose from.¹ A lot of old hardware had similar limitations. Artists who create pixel art may limit themselves to 256 colors at maximum influenced by this.