如何修改Php.ini以启用GD jpeg支持？

I'm using PHP 5.2.0 on IIS 6. I wonder what should I do to enable GD Jpeg support, I've already uncommented extension = hp_gd2.dll in php.ini but still not getting the expected result. Am I missing a step?

EDIT ----------> well using this code:

<?php
function LoadJpeg($imgname)
{
    /* Attempt to open */
    $im = @imagecreatefromjpeg($imgname);

    /* See if it failed */
    if(!$im)
    {
        /* Create a black image */
        $im  = imagecreatetruecolor(150, 30);
        $bgc = imagecolorallocate($im, 255, 255, 255);
        $tc  = imagecolorallocate($im, 0, 0, 0);

        imagefilledrectangle($im, 0, 0, 150, 30, $bgc);

        /* Output an error message */
        imagestring($im, 1, 5, 5, 'Error loading ' . $imgname, $tc);
    }

    return $im;
}

header('Content-Type: image/jpeg');

$img = LoadJpeg('progressive.jpg');

imagejpeg($img);
imagedestroy($img);
?>

I expect to get progressive image load, but I get error instead. - I haven't recompile php after modifying php.ini <------ Should I? if so, how would I recompile php?

Make sure your php.ini file contains a line like "extension_dir="C:\php\ext" replace that file path with the actual location of the dll you are tyring to activate.

you can view below site.This may i think help you a lot to get some ideas.>>

http://forums.cpanel.net/f5/php-gd-jpeg-support-problem-41642.html

or Perl is not installed.

Please check it. I am not 100% Sure. Please Reply if you get the complete answer.,

Thanks