About image steganography
Steganography hides a message in ordinary-looking media. This tool uses the least-significant bit (LSB) of each RGB channel, so changing a channel by one is normally invisible. The encoded result is always downloaded as a lossless PNG.
Capacity and compatibility
Capacity is calculated from width × height × 3 bits, minus a small header used to identify the message and verify its password. JPEG and WebP images can be used as carriers, but the output must remain PNG: saving hidden bits through lossy compression can destroy them.