Jeff Abrahamson on 12 Jan 2006 22:09:58 -0000

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Re: [PLUG] jpeg, 1322 bytes, and iPhoto

On Wed, Jan 11, 2006 at 11:17:22PM -0500, wrote:
>   [66 lines, 317 words, 2363 characters]  Top characters: etioans_
> In the message dated: Wed, 11 Jan 2006 22:05:35 EST,
> The pithy ruminations from Jeff Abrahamson on 
> <[PLUG] jpeg, 1322 bytes, and iPhoto> were:
> => 
> => 
> => I pulled some jpeg files from a compact flash card onto a Mac running
> => OS X.  Some of the photos were touched by iPhoto magic or some similar
> => OS X sorcery.  The result is that I have two copies of 46 photos, one
> => copy touched, the other not.  The apparently untouched files are all
> => 1322 bytes longer.
> => 
> => It's not of practical importance, as the images all look fine, but I'm
> => very curious what happened.  Below is a diff.  The outlier, 1051, was
> => rotated (by iPhoto?).  On each image I've checked, the files are
> => visually identical.  Indeed, using imagemagick to subtract one from
> => the other results in complete black (confirmed with gimp's histogram
> => tool).
> => 
> => Any ideas what might have happened and what 1322 bytes might signify?
> I'm guessing that the retouched photos lack the EXIF data embedded in the 
> original jpeg files. That data typically records information like the time, 
> date, shutter speed, white-balance curve, aperture setting, exposure number, 
> etc.

That was my first thought.  But the exif data appears to be identical
when I just look at it.  In addition, the exif data is stored near the
beginning of the file, but the cmp output says the differences are
much further into the files, well past the exif data (I think).


 Jeff Abrahamson  <>    +1 215/837-2287
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