'Save-as jpeg' filesize TWICE as large in cs3 than in cs2

#1

I know I already have an open question in this thread, but another issue has me boggled. Hopefully this is the last one for the near future :slight_smile:

I was about to make a new avatar to upload to CGTalk, and went to save the file as a jpg, but it was too large a filesize. To see if it was just the file, I opened my current avatar psd file and tried to save it, but again it was too big.

Opening the same photoshop file on my PC running CS2, and on my mac laptop running CS3, the following were the file sizes when saving as jpeg:

JPEG Quality____CS2 PC Filesize _____CS3 Mac filesize
10_____________14.77k___________39.2k
5______________10.87k___________35.0k
1_______________9.47k___________33.5k

(pardon the underlining)

Is this a general thing associated with CS3, or is my laptop just acting as if it is from another dimension again?

Thanks,
Adam

#2

Mac files contain a resource fork that adds to the file size.

From GrimRipperCM 1.4.1:

Resource fork?
What the heck is this? Below is a short introduction for recent switchers.
Resource fork is a legacy thing dating back to Classic Mac OS. Mac OS filesystem allows a single file to have two “forks”: data fork and resource fork. Data fork is usually the main content while resource fork can often be described as some kind of metadata glued to the main content (this is not entirely correct but for the purpose of this discussion should be good enough). Both forks are presented as a single file in Mac OS. With the advent of Mac OS X resource forks have been deprecated but the file system stills allows them you can find them in many places. So why do you care and why one would want to remove those resources? Of course the resource fork takes up the disk space sometimes not providing any useful information — but it is not a big problem given the sizes of modern hard drives. The more important thing is cross platform compatibility. When you send a file by e-mail (picture or document) the resource fork is detached from the original file and you end up sending 2 files. This encoding method is called AppleDouble, when one file with data and resource is split into 2 files. The common situation is that you send a document with resource fork to your Windows friends and they receive 2 files. If the e-mail client they use is not AppleDouble-aware it does not know that it can ignore the file with resource fork data and displays 2 attachments: one document and one that looks like garbage. Your poor friends of course suspect that you sent them a virus. This is a good reason to remove resource fork before e-mailing pictures or documents.

http://www.macupdate.com/info.php/id/9105

If you’re using PS on a Mac, set your Prefs as follows: File Handling>Image Previews>Ask When Saving. Then, when you Save as JPG, uncheck Image Preview: Icon and Mac Thumbnail.

#3

Hey, thanks for the reply! So that’s why I always see two files when transferring to the pc…

I tried modifying the PS settings as you suggest, and when saving as jpg the checkboxes for Icon and Macintosh thumbnail are off (by default). With those confirmed as off, I still get the same file sizes as before. If I turn off the Windows thumbnail, I still can’t drop the filesize below 30k at any quality setting. Do I need to run that program you linked to after saving, or is it only for stripping the resource fork from existing files (as opposed to new jpgs)?

#4

No, the resource fork should already be stripped if you uncheck all Image Preview options. I only have a Mac, so I don’t know what else to look for.

#5

are you embedding the color profile by chance? that will increase the size as well…

#6

Thanks for the reply! I had tried not embedding the profile and that did shave off a bit of the size. However, something else seems to have solved the problem for me…

I received my cs4 upgrade in the mail last week and cs4 doesn’t seem to have the problem anymore :slight_smile: The predicted size when saving is still too large, but the actual size after saving is much closer to the cs2 output size (and small enough). At least it appears to be fixed for now! (even though the predicted size is unreliable)

Thanks for the suggestions to those who replied!

-Adam

P.S. One other thing I picked up: even though cs4 solved the problem that seems to have existed under cs3 and I could export my old avatar properly again, my new avatar was saving too big. I realized that being based on a photo, it contained extra info about the camera embedded in the file, so I flattened the image, and copied it to a new file, stripping out that useless data. (Included this extra para in case it helps anyone else in the future :slight_smile:

#7

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