Problem using GD library ImageJPEG function

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  • André Gasser
    #1

    Problem using GD library ImageJPEG function

    hello newsgroup,

    I just discovered a weird effect in my php code. here is the flow of my
    code:


    1. upload jepg file to server
    2. create new (empty) jpeg file using imagecreatefrom jpeg() function
    3. use imagecopyresamp led to resize src image and store in newly created
    image from step 2.
    4. use imagejpeg to get new jpeg data
    5. store that data in the mysql database

    NOW: when i use imagejpeg using 100% image quality, some images in the
    database are corrupt, but NOT ALL only some of them.

    when i reduce image quality to 60% i had no problem using a picture
    which hat problem with 100%. images are ok this way.

    does this have some logical explanation? is this a bug in the gd or
    something?

    I use PHP 5.0.2, GD bundled (2.0.28 compatible), and mysql 4.x

    I will analyze that code in more detail...


    thanx !
    andré

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    • André Gasser
      #2
      Re: Problem using GD library ImageJPEG function

      André Gasser schrieb:[color=blue]
      > hello newsgroup,
      >
      > I just discovered a weird effect in my php code. here is the flow of my
      > code:
      >
      >
      > 1. upload jepg file to server
      > 2. create new (empty) jpeg file using imagecreatefrom jpeg() function
      > 3. use imagecopyresamp led to resize src image and store in newly created
      > image from step 2.
      > 4. use imagejpeg to get new jpeg data
      > 5. store that data in the mysql database
      >
      > NOW: when i use imagejpeg using 100% image quality, some images in the
      > database are corrupt, but NOT ALL only some of them.
      >
      > when i reduce image quality to 60% i had no problem using a picture
      > which hat problem with 100%. images are ok this way.
      >
      > does this have some logical explanation? is this a bug in the gd or
      > something?
      >
      > I use PHP 5.0.2, GD bundled (2.0.28 compatible), and mysql 4.x
      >
      > I will analyze that code in more detail...
      >
      >
      > thanx !
      > andré
      >
      > ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet
      > News==----
      > http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+
      > Newsgroups
      > ----= East and West-Coast Server Farms - Total Privacy via Encryption =----[/color]


      WOW!

      Images become good if I use the call:

      imageinterlace( $myimage, true);

      the doc says, that in this way, a progressive jpeg is created.

      they even get good if I use a quality of 100%!!

      very strange......

      can someone explain this behaviour to me? thx! :-)

      ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
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