Hide any image inside another one by rearranging its pixels. Upload a source photo — its pixels get disassembled, sorted, and reassembled to recreate a completely different image. Same pixels, new picture. Try it.
Your source image is disassembled into individual pixels — every single one is extracted.
Those pixels are sorted into an inventory by the chosen criterion (e.g. luminance: darkest to brightest), forming a smooth gradient.
Pixels are pulled from the inventory and placed one by one into positions that recreate the target image. Dark pixels go where the target is dark, bright ones where it's bright.
The result uses only pixels from your source — nothing is created or modified. It's a pure rearrangement.