Steganography: Hide a Message in an Image

Hide secret text or a small file inside an ordinary-looking picture, protect it with a password if you like, and reveal it later with the same tool.

NewFreeNo uploadAES-256 option
1Choose what to do
2Secret message
0 B usedCapacity: upload an image
3Protection
Hiding strength

1 bit per colour channel changes pixels by at most 1 level, which is invisible. 2 bits doubles the space with a still very subtle change.

How to use Steganography

  1. 1

    Upload a cover image

    Any photo works. Larger images can hold more hidden data.

  2. 2

    Write your secret

    Type a message or attach a small file, and optionally set a password for AES-256 encryption.

  3. 3

    Download the PNG

    Share the PNG file. To read the message, open Reveal and upload the same file.

What is steganography?

Steganography is the art of hiding information inside something that looks ordinary. Unlike encryption, which shows that a secret exists, steganography hides the fact that there is a message at all. This tool hides your text or file in the least significant bits of the image pixels, changing each colour value by at most one or two levels, which is invisible to the eye.

How to use it

  1. In Hide a message, upload a cover image, type your message or attach a small file, and optionally set a password.
  2. Download the result. It is always a PNG, because PNG is lossless and keeps every pixel exactly.
  3. The recipient opens Reveal a message, uploads the PNG and, if needed, enters the password.

Password protection

With a password, the hidden data is encrypted with AES-256-GCM using a key derived with PBKDF2 (SHA-256, 200,000 iterations) and a random salt. Without the password, the message cannot be read, and any tampering is detected.

Keep the PNG intact

The hidden bits survive only in the exact original file. Converting it to JPG, resizing, editing, taking a screenshot, or sending it through apps that compress images (WhatsApp, Facebook, Instagram, many messengers) destroys the message. Email attachments, cloud storage links and file transfer services keep it intact.

How much can I hide?

With 1 bit per colour channel, a 1920 × 1080 image can hold about 760 KB. The capacity meter shows exactly how much space your image has; "More space" (2 bits) doubles it with a change that is still very hard to see.

All processing happens locally in your browser: your images, messages and passwords never leave your device.

Frequently asked questions

Is the hidden message visible?
No. Each colour value changes by at most 1 level (or 3 with More space), which cannot be seen. The image looks identical.
Why must the image stay PNG?
PNG is lossless, so every pixel is kept exactly. JPG compression, resizing or editing changes the pixels and destroys the hidden data.
Can I send it on WhatsApp?
Not as a photo, because WhatsApp compresses images. Send it as a document/file, by email or via a cloud link instead.
How secure is the password option?
The data is encrypted with AES-256-GCM and a PBKDF2-derived key, so it cannot be read without the password. Use a long, unique password.
Can I hide a file instead of text?
Yes. Attach a small file; it is restored with its original name when revealed. The capacity meter shows the maximum size.
Can this tool read messages hidden by other apps?
Usually not. Each steganography tool uses its own format. This tool reveals messages created with imagetools.to.
Is anything uploaded?
No. Everything runs in your browser.

Related tools

EXIF RemoverImage to Base64EXIF ViewerImage to Text (OCR)