Hide a note inside an image

Least-significant-bit steganography: tuck a text message into a PNG's pixels, invisibly — and extract it back.

Tools used in this guide

The job

Steganography hides that a message exists at all: flip the lowest bit of each color channel and the change is invisible to the eye, but a reader can pull your text back out. Good for hidden tags, puzzles, watermark notes.

Embed and extract

Choose a PNG, type the message, embed — the tool writes a length header plus your bytes into RGB least-significant bits and gives you back a PNG that looks identical. To read a message back, drop a stego'd image into extract mode.

Capacity is about 3 bits per pixel minus a 32-bit header — a 1000×1000 image holds ~375 KB, way over the 65,535-byte message cap.
Must stay PNG: re-saving as JPEG scrambles the low bits and destroys the payload.

Worked example

Embed 'meet at the usual spot' into a vacation PNG. Visually identical, a few hundred bytes of RGB LSBs changed. Anyone with the tool extracts the text; anyone without it sees a photo.

Where it stops

LSB steganography is secrecy by obscurity, not encryption — anyone who suspects the payload can read it; encrypt the text first if it matters. Payload survives only lossless handling: JPEG re-save, resize, or filter destroys it. Source images up to 32 MiB; alpha channel untouched.