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I have a chunk of a PNG file, missing its end. An unknown amount of data from the IDAT chunk is missing, as well as the IEND chunk. I've inspected the IHDR and it looks completely fine, correctly showing the image size (1920x1080), bit depth (8), etc. The image is not interlaced.

I'm on Windows (but have a Linux box available). Opening it in Windows just gives a black window, no content (but also no error messages).

Is there any way to render what I have of the image? Or is the entire thing unreadable because the bottom part is missing?

The data is also noisy, but I don't expect it to cause much of a problem - the S/N ratio should be pretty high and, as I said, the IHDR is completely fine.

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  • What OS are you attempting this recovery on? What happens if you try to open the damaged file? – Giacomo1968 Aug 27 '18 at 17:04
  • I'm on Windows (but have a Linux box available). Opening it in Windows just gives a black window, no content (but also no error messages). – realityChemist Aug 27 '18 at 17:05
  • Off the top of my head, my quickest idea for recovery would be to use a command line tool like ImageMagick on Linux and just run the command convert damaged_file.png recovered_file.png. I believe the act of simply “converting” the PNG from one PNG file to another via ImageMagick will help you render whatever data contained in the image still remains. – Giacomo1968 Aug 27 '18 at 17:10
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    Interesting! Tried this and got an error (first one!): IDAT: Invalid distance too far back. Gonna follow this one down the rabbit hole and see if I can fix it. – realityChemist Aug 27 '18 at 18:06
  • “Gonna follow this one down the rabbit hole and see if I can fix it.” Well, please be sure to take a nap every now and then! But seriously, I think if you can find some tool that can open the file, then you can easily save it again and have something. – Giacomo1968 Aug 27 '18 at 18:08

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