"Optimize to file size" script

[linesandwaves]

Hi everyone,

I am currently writing a script to circumvent Photoshop's lack of scripting support for the "Optimize to File Size" option in the Save for Web command, but I'm having trouble with targeting the file sizes correctly.

Here is the code I'm using (forgive me, I know its not so graceful... I'm still very new). Basically it exports the image at 100% quality, checks the resulting file size against the desired file size, and if it's not equal to or less than that value, it deletes, reduces the quality level, and re-exports until it meets that criteria:

Code: Select allon optimizeFile(currentDoc, optimizeSize, exportPath, fileExtension, trimmedFilename, qualityIncrement)
   set qualityLevel to 100
   set optimizedFile to ((exportPath & trimmedFilename & fileExtension) as string)
   
   tell application "Adobe Photoshop CS3"
       tell currentDoc
           export in file optimizedFile as save for web with options {class:save for web export options, quality:qualityLevel, web format:JPEG}
       end tell
   end tell
   tell application "Finder"
       set truncatedFile to files of alias exportPath whose name contains "#0"
       repeat with thisFile in truncatedFile
           set name of thisFile to (trimmedFilename & fileExtension)
       end repeat
       set fileSize to physical size of optimizedFile
   end tell
   repeat until fileSize is less than or equal to optimizeSize
       tell application "Finder"
           delete file optimizedFile
           set qualityLevel to (qualityLevel - qualityIncrement)
       end tell
       tell application "Adobe Photoshop CS3"
           tell currentDoc
               export in file optimizedFile as save for web with options {class:save for web export options, quality:qualityLevel, web format:JPEG}
           end tell
       end tell
       tell application "Finder"
           set truncatedFile to files of alias exportPath whose name contains "#0"
           repeat with thisFile in truncatedFile
               set name of thisFile to (trimmedFilename & fileExtension)
           end repeat
           set fileSize to physical size of optimizedFile       
end tell
   end repeat
end optimizeFile



The problem that I am having is that when this script exports bigger images at bigger file sizes (even in the 30 to 40k range) it works perfectly. However, whenever I get to thumbnail sized images that i need to export at say 3k or 4k, it runs into an infinite cycle of deleting and re-exporting. I have tried using the "data size" property instead of "physical size" but that seems to ignore the loops altogether and export files at much larger sizes.

Can anyone out there help? I'd love to nail down a script that can do this function well, as I think there is a huge need for this functionality amongst people who regularly batch process images, i'm just afraid that my version may not be the most efficient.

[Patrick]

I would guess that there are some small sizes that are impossible to reach with certain images, thats why it keeps trying infinitely. Only thing I would suggest is have some sort of fail condition added to allow the script to abort without an acceptable export... maybe after the qualityLevel is < 10. Just an idea,

Patrick

[Mike Hale]

I don't know applescript but I will bet that finder is reporting the file size as stored on the disk and because of sector sizes it will never get below the sector size. ie a one byte file still takes up a full sector.

You may want to post this at the Adobe forum. There are more users using applescript there than here.


Mike