Provide a sample (and little) script and the images causing your problem may help.

For what you said, the "random" color may in fact be the background. You have to set the transparent color yourself to the dest image.

Short version, it's not a bug as far as I can tell now.

I keep this bug to bogus, if you have a reproducable script with one image, turn it back to open.

I have already provided a sample script, which is available on
http://thomaskeller.biz/work/php/PHP_GIF/image.php, the source for this file is  http://thomaskeller.biz/work/php/PHP_GIF/image.phps [0].

The test image which fails to be scaled is http://thomaskeller.biz/work/php/PHP_GIF/rose.gif

As you can see here [0] the problematic code seems to be (shortened):

<?php
$idx = imagecolortransparent($im_src);
if ($idx > -1) // transparent color found?
{
    list($r, $g, $b) = imagecolorsforindex($im_src,$idx);
    $transColor = imagecolorexact($im_target, $r, $g, $b);
    imagecolortransparent($im_target, $transColor);
}
?>

where I try to receive the index of the transparent color
of the original image, then find the rgb value of this color and finally create a new color on the target image using the rgb value and set it as transparent color.

RTFM: http://www.php.net/imagecolortransparent

Again it's not a bug.

You have to set the transparent color correctly in the destination image.

--Pierre

> Again it's not a bug.   
> You have to set the transparent color correctly    
> in the destination image.   
  
So what means "correctly" here? I've tried several  
dozens of combination to get the desired result  
but failed with each. I copied palettes over, tried to  
copy into a 32bit target image while later shrinking  
it back via imagetruecolortopalette, and more.  
I'll promise I'll shut up if you just give me a few   
lines of CORRECT code. The docs don't help me on my  
problem.  
  
I've also noticed that a list($r, $g, $b) =  
imagecolorsforindex(...) doesn't work as suspected,  
because all three variables are unset. This is my  
current code:  
  
<?php  
$im_source = imagecreatefromgif($somefile);  
$im_target = imagecreate($width, $height);  
$idx = imagecolortransparent($im_source);  
$rgba = imagecolorsforindex($im_source, $idx);  
imagecopyresampled($im_target,$im_source, 0, 0, 0, 0,  
  $new_width, $new_height, $orig_width, $orig_height);  
$transColor = imagecolorallocate($im_target,  
  $rgba['red'], $rgba['green'], $rgba['blue']);   
imagecolortransparent($im_target, $transColor);  
header("Content-type: image/gif");  
imagegif($im_target);  
exit;  
?>  
  
imagecolortransparent on $im_target afterwards returns  
the index for the transparent color (white), but still the  
background of the image has another color (rgb 128,64,88).  
If I set this color to be transparent, nothing happens  
(its still there).