To Insert a hidden message into an image:

1. Upload an image
2. Place some text in the textarea
3. Click "Insert"

An image should then appear at the bottom of the page, now containing a hidden message.

To Extract A hidden message from an image:

1. Upload an image
2. Click "Extract"

The text from the image should appear at the bottom of the screen.

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This script works by slightly altering the pixels evenly across the entire image. This makes noticing that the image has been edited in any way difficult.

The first 4 pixels of the image are used to note how many pixels were changed in the image. This is enough information for the script to reconstruct the original message.