Stolen Cross-posted from here: https://fosstodon.org/@foo/113731569632505985
Actually, you can consider RGB values to be (triplets of) floats, too.
Typically, one pixel takes up up to 32 bits of space, encoding Red, Green, Blue, and sometimes Alpha (opacity) values. That makes approximately 8 bits per color channel.
Since each color can be a value between 0.0 (color is off) and 1.0 (color is on), that means every color channel is effectively a 8-bit float.