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(Archived) jpeg into EN 780KB then out 688KB - why?


Migs

Idea

Friends:

I wonder why an image dragged into EN degrades in size. Ideally one should be able to extract exactly what was put in. For example: I drag into a new note a jpeg of 780KB and drag it back out (control click save as) the file is now 688KB.

I wish EN would respect the file.

Migs

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16 replies to this idea

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With Louis's help, I was able to reproduce this on my machine. The results are extremely weird.

He sent me a ZIP file with a JPEG in it that expands into something that appears to be 536kB in the Finder, and the Unix 'du' command also reports that same size:


~/Downloads $ du -hs picShrinks.jpg
536K picShrinks.jpg

If I drag it into Evernote and then drag it back out again, I get something that seems to be 444kB in the Finder and 'du':


~/Downloads $ du -hs draggedFromEvernote/picShrinks.jpg
444K draggedFromEvernote/picShrinks.jpg

BUT ... if I actually dig into the file a bit, it appears to be identical. And the Unix 'wc -c' command (which reports the number of bytes in the file) says the two are identical:


~/Downloads $ wc -c picShrinks.jpg draggedFromEvernote/picShrinks.jpg
453326 picShrinks.jpg
453326 draggedFromEvernote/picShrinks.jpg

It turns out that the difference is hidden Mac file system metadata that the Mac is storing in a hidden place in the *folder*, not in the actual file itself:


~/Downloads $ unzip -l picShrinks.jpg.zip
Archive: picShrinks.jpg.zip
Length Date Time Name
-------- ---- ---- ----
453326 01-12-10 00:52 picShrinks.jpg
0 09-11-10 17:58 __MACOSX/
91006 01-12-10 00:52 __MACOSX/._picShrinks.jpg
-------- -------
544332 3 files

In every Mac folder on your system, there's a hidden ".DS_Store" file that contains Mac-specific information about the files and layout of that folder. It appears that if you use the Mac UI to zip a file, it will grab the relevant chunk from the .DS_Store file and hide it in a __MACOSX/ virtual folder within the ZIP file. Then, if you extract that on a Mac, it will stuff the magic information back into the .DS_Store file in the corresponding directory.

If, on the other hand, you try to use the file in any cross-platform context (like Evernote), this extra magic Mac file system metadata goes away, and you only see the original (real) file itself.

So ... TL;DR - Evernote will keep the real original JPEG when you add it to Evernote, but it won't preserve the special Mac-only file system metadata. I'm pretty sure you'd get the same result if you sent the file via web-based email, etc.

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Here's a theory that, even if false, points up a significant issue:

I am regularly frustrated by software that simply discards metadata from photo files whenever it touches them. Yes, I'm looking at you, Preview (and many others). Is it possible that the original photo had a large chunk of metadata that was lost when EverNote saved the file? This would not, of course, change the actual image.

For those who are interested (and I hope you all are), the Metadata Working Group is defining a set of recommendations for handling metadata in consumer images. Please support them in convincing the industry that it's NOT OK to simply toss out metadata.

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Interesting...I'm noticing the same behavior. Using a JPG image, went in 549 out 455. The behavior appears both before and after syncing. (doesn't matter when you drag the picture out).

jbenson2 - no, the image does not shrink a second time. Apparently whatever changes are happening only happen once.

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  • Level 5

I don't have a Mac, perhaps someone else could duplicate the problem.

I am curious - what happens if you take the smaller photo and run it through Evernote a 2nd time?

Your 1st pass took the photo from 780KB to 688KB.

Will the 2nd pass take it from 688KB to something smaller?

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  • Level 5

Hmmm, that is a perplexing issue.

I just tried it with Windows 7 / Evernote 3.5.6.2848 (98771) It went in at 858KB and came back out at 858KB.

To get the photo back out, I right-clicked on it and saved.

Is there any chance you opened the photo with some Apple software and then saved?

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