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02/24/2005 12:22:16 AM · #1 |
I'm not sure how this happens or if it happens frequently, or if someone has asked this in a prior question.....
The properties of Kiwiness's photo for the self-portrait challenge "Layer mask" shows a image of 588x640 with a file size of 157944 bytes.
Advanced editing specifies a file size of no larger than 150k, 153600 bytes. If a user tries to submit an image larger than this size for a challenge, the user is given a warning message and the photo is not submitted.
How is it possible that Gary's photo shows a file size outside the limits of the challenge? |
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02/24/2005 12:41:58 AM · #2 |
After the file upload is finished, the size is checked to make sure it is 150K (153,600 bytes) or less.
After the file is accepted, though, it is "processed." Any extraneous non-image markers in the JPEG (such as Adobe XMP data, EXIF data and color profiles that might be embedded) are removed via the 'jpegtran' utility to maximize browser compatibility. During this time, the image data is also losslessly recompressed, and in some cases JPEG file actually gets slightly bigger in the process.
As such, an entry that was within the legal limits at upload time may increase beyond that limit after it is uploaded. The limit is based upon the uploaded size, not the size after we process the file for posting.
-Terry
Message edited by author 2005-02-24 00:42:40.
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02/24/2005 12:56:38 AM · #3 |
Thanks Terry. I also see an entry of mine that is over 161000 bytes,
over 8k larger than the size submitted. |
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02/24/2005 03:11:44 AM · #4 |
By the same token, several times I have compressed a 640-pixel image in PS to something like 149 kb, only to be told, when I tried to submit it, that it exceeded the filesize limit. So I deduce that when I upload it I am also including tags that are not part of the "native" image, and they are increasing the filesize by more than 1 kb.
What's really frustrating about it is that when this happens I lose all the data I have entered into the submission fields, and have to start from scratch after I compress it another notch in PS. Is there any way to fix it so the data remain intact for another try?
Robt.
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02/24/2005 03:16:30 AM · #5 |
Originally posted by bear_music:
....... Is there any way to fix it so the data remain intact for another try?
Robt. |
Hear! Hear! |
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02/24/2005 03:45:00 AM · #6 |
Hey Robert,
If you save as when editing, then look at the properties of that image, there will be an image size and file size on your drive. That's why it's going over the 150K limit. Are you saving for web in PS? That will strip out non-image data from the recorded file.
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02/24/2005 03:50:54 AM · #7 |
No, I've never "saved for web" because I didn't trust it not to do something I didn't want done, artefact-wise. Are you telling me that's not an issue?
Robt.
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02/24/2005 04:25:29 AM · #8 |
Saving for web will give you the most uncompressed image data as compared to Save As. The Sva As file will always be larger, because it contains all teheimage shooitng data like EXIF for one. Using Save for Web, all that is removed, allowing you to finely adjust the image right up to 150K, thus compressing the image less and leaving less jpeg compression artifacts in your submissions.
It the way most of us do it to get the most image quality up to 150K.
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02/24/2005 09:41:41 AM · #9 |
I concur with BradP; my experience with both "Save as" and Save for Web" indicate that the latter is a much better path when you need to ensure that a file meets an absolute file size limit. I use Save for Web exclusively for my DPC images. For other sites, where I want EXIF preserved and I'm not concerned with an exact file size target, I use Save As.
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02/24/2005 10:17:16 AM · #10 |
For anyone that may have questions on this using Paint Shop Pro (version 9) the File/Save As gives you some choices by using the 'Options' button. Select 'Options' and you can deselect EXIF data and you also have the option of manually setting compression or using the 'Run Optimizer' button. The Optimizer will show you the file size as is, and the file size as you change the compression ratio.
Take care. Barry
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02/24/2005 10:46:06 AM · #11 |
In Photoshop's Save As dialog there should be a checkbox to "Exclude Non-Image Data" which should strip out the excess EXIF, and probably any entries in the File Info ... fields as well.
I don't have Save For Web in the version I use. |
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02/24/2005 11:20:14 AM · #12 |
Originally posted by GeneralE:
In Photoshop's Save As dialog there should be a checkbox to "Exclude Non-Image Data" which should strip out the excess EXIF, and probably any entries in the File Info ... fields as well.
I don't have Save For Web in the version I use. |
I believe that when Adobe implemented "Save for Web" they also changed the "Save As" options. In CS, and in 7.0, the option to exclude non-image data no longer exists. That function is provided by "Save for Web." I don't know offhand wht version first had this change.
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02/26/2005 10:40:43 PM · #13 |
Originally posted by BradP:
Hey Robert,
If you save as when editing, then look at the properties of that image, there will be an image size and file size on your drive. That's why it's going over the 150K limit. Are you saving for web in PS? That will strip out non-image data from the recorded file. |
Thanks Brad. I didn't realise that & appreciate the tip! |
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