Replace each visible RGB channel with its 8-bit complement.
The frame below runs the same code as this page, in the reader's own browser. Nothing is sent to us, and nothing is sent to you.
Pick a dark background and the text and panels follow it, so the frame stays readable on a dark page.
Every RGB channel becomes 255 minus its current value, then Canvas redraws the image at its original size and emits PNG. Alpha is not inverted.
data:image/png;base64,iVBORw0KGgo=
PNG data URL with each RGB channel complemented
Design mock-ups preview negatives, dark-mode experiments test inversion, and graphics lessons demonstrate RGB complements.