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Old Jun 11, 2006, 11:53 AM   #1
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Hi guys - Some websites [like Steve's] require postings of pics based on memory size [eg: 245kbs] rather than dimensions. Does anyone know of a means of batch resizing based on kilobytes, either with Photoshop, or some other software.

Thanks in advance !!
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Old Jun 12, 2006, 10:38 PM   #2
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Interesting question. I looked into it a bit but I don't see any way to do that using Photoshop or any of the software I use. You can pretty reliably batch compress images to under a certain size by just making sure you resize them down to something relatively small. For example, if you resized and saved a batch of images to 640x480 as high quality (60/100) JPGs, you probably wouldn't see many images bigger than 120kb.
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Old Jun 13, 2006, 1:07 AM   #3
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Thanks for the reply, corpsy - yes there are various methods of batch resizing, I suppose what I am looking for is to get Maximum quality [IE: if 245kb is max accepted, then what I try and do is getthe resize as close to 245kb as possible]. Photoshop and all the other software I knowhas the 0-12 steps of jpgquality saving[after the image resizing], and it's not very accurate and takes a few trial and error resizes and savings to get the desired kbs.

I found this link on a google search, but the solution is avaliable to paid members only

http://www.experts-exchange.com/Web/..._21859992.html
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Old Jun 13, 2006, 9:41 AM   #4
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You want to do both here (resize for dimensions and file size).

Otherwise, your photo will not render correctly (the dimensions will be too large for many browsers the way the forums software works with them, and even if you get it to display, that means users would need to scroll back and forth to see the text in forum entries in a thread you post in, since it makes the lines longer before word wrap.

As a general rule, I use http://www.irfanview for both upsizing and downsizing an image.

Usually, I'll limit the width to around 720 pixels wide for a landscape oriented photo, and around 532 pixels wide for a Portrait Oriented image (since that puts the long end at around 800 pixels, and users would need to scroll up and down to see the entire image if you made it much larger).

After downsizing, use the JPEG Quality slider you see pop up when you use the "Save As" option and give it a new filename. Lower Quality = Higher Compression = Smaller File size. With an image resized for web viewing in the forums, I usually save at around 85 - 88% quality using Irfanview to keep the file size relatively small (between 100 and 200KB).


Most image editors have similar functions (resize images, specify jpeg quality when you save them to disk).

Irfanview also works in batch mode.

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Old Jun 13, 2006, 9:47 AM   #5
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Thanks JimC - I do use the methods you described, however,what i am looking for is ameans of batch processing both types, so one can specify dimensions as well as Kilobytes:-)
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Old Jun 13, 2006, 9:55 AM   #6
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Irfanview works in batch mode and lets you specifiy the length of the long side when resizing multiple images in batch.

You can also specifiy the JPEG quality used for batch processing (under options on the batch processsing screen when output filetype is set to jpeg). If you set it at 85%, they'll be small enough if you resize the long side to 720 pixels.
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Old Jun 13, 2006, 9:59 AM   #7
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This still leaves the kb's side of it pretty much up to chance -There must be a way to get the kB's as close to what you want by specifying the size [in kb's] [hey, it's only digital data, it has to do what it is told :lol:]
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Old Jun 13, 2006, 10:05 AM   #8
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JakeTPegg wrote:
Quote:
This still leaves the kb's side of it pretty much up to chance -There must be a way to get the kB's as close to what you want by specifying the size [in kb's] [hey, it's only digital data, it has to do what it is told :lol:]
85% quality is good enough for web viewing, and keeps the file sizes reaasonable. Sometimes, I even use more compression (if I'm posting a lot of photos). Keep in mind that some users don't have high speed internet access. ;-)

JPEG images vary in size based on their content. An image that has more detail and colors may be larger than an image that has less detail and colors.

So, in order to compress files to the same files sizes, the batch processing algorithms would have to be more complex, varying quality (more or less compression) between photos to keep the identical file size.

With Irfanview using 85%, file sizes tend to run pretty close together though for images shot in the same conditions. You could go less compression for some images. But, I usually don't go more than 87% quality keep file sizes down for our dial up users.


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Old Jun 13, 2006, 10:38 AM   #9
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Thanks Jim, appreciate the info !
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Old Jun 13, 2006, 1:12 PM   #10
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Have a look at http://www.stevesforums.com/forums/v...amp;forum_id=9




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