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Old July 18th 20, 04:34 PM posted to rec.photo.digital,sci.engr.color,sci.image.processing
Martin Brown[_2_]
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Posts: 17
Default tag for edited file

On 17/07/2020 22:21, dale wrote:
What about a tag in an image file indicating it is not the original?


Utterly pointless. Anyone that understands the file formats can tell if
something has been through one of the common image editing programs and
many cameras include enough meta information and use custom quantisation
tables in their JPEGs to effectively have signed the original image.

You cannot stop someone producing a convincing edited fake that looks
entirely authentic using already existing tools.

Taking it further, what about including each edited image in the file?


If you want the file size to grow exponentially then why not?

Strangely NASA have a bug in their workflow that means sometimes they
publish images which contain two or three identical thumbnails with a
brace of original images concatenated. Unclear how or why they do it.

Mickeysoft Word does that sometimes to corporate documents where users
drag and drop images into report templates originally written in a
legacy version. The document grows exponentially in size each time it is
edited with different versions of Word as more and more orphaned image
data accumulates in the file with each iteration.

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Regards,
Martin Brown