Every one of the 16,777,216 possible RGB colors appears in this image exactly once, and yet it still reads clearly as a landscape: a mountain ridge, a setting sun, a lake reflecting it all back. That combination shouldn't really be possible. Real photos repeat colors constantly (skies, shadows, water are mostly the same few tones over and over), so squeezing in the entire color space without any repeats normally means giving up any resemblance to a real scene.
The workaround was to start with an ordinary-looking sunset, then match its colors to the full palette by rank rather than by exact value. Every pixel in the original scene and every color in the 16.7 million-color set got sorted using the same rule, then paired up one to one in that order. That keeps the shapes, edges, and gradients from the original intact, but it stretches the small, natural range of colors a real image would use out across the entire spectrum. So the mountains and the sun and the lake are all still there, just rendered in a blown-out, neon, almost thermal-camera palette. That vivid, banded color is the visible price of the constraint: a real photo could never legitimately contain all 16 million colors without being pushed that far.
