Just thought I'd add how I used the gamma correction function (seeing as no-one had done so previously). works great.
I used a form which has a parameter $GAMMA, so I usually type in something like 1.6
$image = ImageCreateFromJpeg ( "pictures/".$PICTURE2 ) ;
if ($GAMMA != "")
{
$GammaFloat = (double) $GAMMA ;
imagegammacorrect ($image, 1.0, $GammaFloat ) ;
// now save the file
imagejpeg ( $image, "pictures/"."$PICTURE2", 90 ) ;
}
imagefttext