File talk:StenographyOriginal.png

Cranraspberry (talk) 04:21, 24 April 2009 (UTC)
 * I have tried decomposing this image and see no hidden image underneath. In GIMP I set RGB to 2/100 in each channel, and increased the brightness of the image until it was evident there was no stenograph. What am I doing wrong? Is this not the same image described?

The steps needed to reproduce this (on linux) follow (a friend just asked me how ;).
 * Download StegnographyOriginal.png

wget http://upload.wikimedia.org/wikipedia/commons/4/4e/StenographyOriginal.png
 * Convert it into BMP using imagemagick

convert StenographyOriginal.png SO.bmp
 * Now load up python, and do some bit manipulation:


 * (Optional) Convert it back to a png

convert cat.bmp cat.png

Hope this is useful - there may be a nicer way of doing it for GUI people, but I dunno. Conrad.Irwin (on wikt) 19:05, 26 May 2009 (UTC)

Decoding with PhotoShop
I have attempted to decode this steganographic image with PhotoShop. No luck. I would think you could do it with the following steps:

- Brighten image until all but the two LS bits of the image are clipped to white. - Darken to a medium gray. - Increase contrast to bring out image.

(The Equalize command might even do the last two steps automatically.)

When I do these steps, I find no hidden image. Does the PNG perhaps store the image with a channel depth of greater than 8 bits? If so, then the example really is not fair; Screens are displayed with a 8 bit channel depth. If the steg image is displayed in bits beyond those eight, they will be simply discarded by hardware. RastaKins (talk) 19:23, 2 August 2010 (UTC)


 * Not "fair"? That's the point of steganography &mdash; the hidden image should remain hidden unless one has the requisite tools and knowledge to extract it.  If most standard hardware is incapable of displaying the information without some low-level bit diddling pre-processing, then so much the better.&mdash;QuicksilverT @ 23:53, 31 January 2011 (UTC)