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It's in the bag.
VAXHOLM (Rixstep) — Following up on yesterday's delectable discovery in /System/iOSSupport on Mojave systems: the 32x24 PNG image MessagesDefaultIcon-32.png weighing in on disk at 10.3 MB (10,265.058 bytes).
Here it is again.
The mystifying puzzler of course was how such a thing could be possible. An image of that size has only 768 pixels...
Can it be possible?
The image has no colour profile - the most common source of bloat. And it doesn't have any extended attributes either.
So wherefore is it bloated?
A look into the file with Xstrings reveals a lot of non-binary data. (The Xstrings textual 'export' is over 12 MB and so can't be reproduced here.)
But a look at that Xstrings export reveals a number of Adobe URLs and a few curious XML tags, whereof 'photoshop:ColorMode' and 'photoshop:DocumentAncestors' seem the most interesting.
And the latter of those two pays off.
This article from Down Under, by Stephen Marsh in June 2017, pretty much explains it all.
Metadata Bloat – photoshop:DocumentAncestors
'A small but growing number of Photoshop users have been noticing and complaining of excessive, bloated file sizes with certain files saved from Photoshop. In most cases, this is due to Photoshop specific metadata known as photoshop:DocumentAncestors being written to the file.'
'This metadata is added as a record of copy/paste or placed document ID entries. Generally, this metadata is small and does not greatly impact the file size of Photoshop or other file formats containing this historical metadata. However, some users have reported files with excessive amounts of this metadata. What is considered excessive? Metadata does not add that much to file size, does it? Well in some cases 100,000 lines of photoshop:DocumentAncestors metadata has been found! A 65mb file may be reduced to 110kb once this metadata has been removed.'
Hey dude, try 1,929 bytes. Cheers.
'Writing photoshop:DocumentAncestors metadata to a file is not a bug, however I find it hard to believe that an average user could intentionally perform actions in the normal course of working an image that would result in 100,000 entries taking place.'
How about - hold onto your seat - 144,076 entries? (People can contact Adobe support if they have any further questions.)
'Photoshop does offer Export and Export/Save for Web options that do feature the ability to strip metadata from saved files.'
Ah. But this is only a 10 MB file, deposited on the SSDs of unwitting macOS users, so no big deal. Thanks anyway.
'Adobe don't offer a Photoshop preference option to turn this specific metadata on/off.'
Why would they? Are you a Geschke/Warnock troll? Who do you work for?
Now over to Adobe Forums.
'I have a JPG that I have removed all image from, and filled with white. When I save it, the size is 7.89 MB.'
And? Another troll.
Conspiracy Theories Can Be Very Real™
Scooting over to Stack Exchange...
Gotta be the Russians. Back up your system. Contact the FBI. Do it now.
'Further analysis revealed that the file contains over 60000 lines of metadata, consisting mostly of tags inside <photoshop:DocumentAncestors>.'
Ah, dude. Millions of Mojave users would feel your pain. Maybe.
'File seems fishy to me. At best it's bad practice (SEO / Webmaster wise) to have a >3mb file size for a 16x16 icon.'
But this does seem to set a new world record. On Apple systems at any rate. The 32x32 TIFF made by Buzz was only 357,284 bytes on disk.
No results found for MessagesDefaultIcon-32.png.
- Adobe Photoshop
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