Get info shows wrong file sizes?

Question

Get info shows wrong file sizes?

I have several files, mostly Photoshop files, which are reported as one size by the Finder (both in list view, and by get info), and as a totally different file by, e.g. ls -l from a terminal window. The numbers out of ls are clearly correct.

What magic is OS X using to get the file sizes in the finder? Are they cached?

Thanks,
Bob Sidebotham

Posted on Oct 17, 2005 8:06 PM

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Answer 1

Oct 17, 2005 9:25 PM in response to Bob Sidebotham

I don't use Photoshop, but if it stores anything in a file's resource fork (such as thumbnails or a custom icon for the file perhaps) that would account for the difference.

Finder and Get Info will report the total size of both the data fork and the resource fork combined, while "ls" will only show you the size of the data fork.

You can easily see this by examining an alias file, which stores all of it's info in resources in the resource fork of the file. Finder and Get Info will show the alias has a size of 40K or so, while "ls" will show a size of zero.

Steve

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Answer 2

Oct 17, 2005 10:18 PM in response to Steve Herman1

Thanks for the info, Steve. From a usability POV I'm not entirely happy with this: if I email the file to someone, they are only going to see the data fork (I assume). That's the size I'm interested in, in this instance, and in many others. There's a huge difference between a 55KB jpg and a 120KB jpg (which is what the finder reports). The finder actually seems to know that the file is a jpg, and even knows the image dimensions. If it knows all that, it should be able to tell me the actual size of the jpg, which is a very important piece of information to many users, e.g. web designers.

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Answer 3

Kevin Horn

Level 4

1,836 points

Oct 17, 2005 11:13 PM in response to Bob Sidebotham

Photoshop adds lots of extra information to jpegs. You can open it in Preview and export it as a jpeg from there and you'll see a much smaller file, probably that 55kb size.

Best if you have a Photoshop or TIFF file for that because saving a second time as a jpeg will cause more image damage.

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