What is 2⁸, and why is it the most important power of two for bytes?

256 — the number of distinct values a single 8-bit byte can hold (0–255).

Chunk 256 → 25 · 6 → nail · shoe: a nail through a shoe. Because a byte is 8 bits, it has 2⁸ = 256 possible values, which is why colour channels run 0–255 and why 255 (=2⁸−1) is the largest unsigned byte.

Tip: 256 values but the max is 255 — the off-by-one that trips everyone up (counting from 0).