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  1. #1
    Registered User
    Join Date
    Jul 2004
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    3

    Different image editor program effect to file size?

    I ever compare saved PNG File with Photoshop and Grim (on linux). Their size are quite different, may because of compression level. So these different of file size will effect to game performance at run time? Thank you for your help.

  2. #2
    Regular Contributor
    Join Date
    May 2003
    Posts
    72
    Most of the extraspace comes from extra "chunks" of data like timestamps and creator information. Look on the web for the app "pngcrush" and check the below thread for more PNG related info.
    http://www.j2me.org/yabbse/index.php...sg4452#msg4452

  3. #3
    Regular Contributor
    Join Date
    May 2003
    Posts
    72
    Forgot to mention, when you have pngcrush this command line is pretty good at removing all the unnecessary info and shrinking the data part:

    pngcrush -d img_cmp -rem alla -brute *.png

  4. #4
    Registered User
    Join Date
    Apr 2004
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    3
    pngout is also good commandline tool for png files
    Last edited by olgger; 2004-08-17 at 07:43.

  5. #5
    Regular Contributor
    Join Date
    Aug 2003
    Location
    uk
    Posts
    232
    Another alternative is to use Gimp.

    Assuming you don't mind the palette being messed with:

    - Load the image

    - Convert it to RGB
    image->mode->RGB

    - Convert back to indexed
    image->mode->Indexed

    Choose 16 for Max Colours (assuming you can afford to lose that many)

    Tick "Enable Dithering of Transparency" if the image has any transparency

    Then save the Image.

    On the Png save options screen,
    Untick everything (they reprosent the optional chunks), make sure compression is set to 9.

    Note: you may get some odd results, for example, despite asking for only 16 colours, gimp will sometimes put the output file in 8bit rather than 4bit colour. Testing shows this is because oddly, in these few examples, a 8bit palette results in a smaller file than a 4bit palette.

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