I'm looking for cloning an image in PHP created with imagecreatetruecolor
or some other image creation function..
As it was said in the comment, no you can't do a simple affection like :
$copy = $original;
This because ressources are reference and could not be copied like scalar values.
Example :
$a = imagecreatetruecolor(10,10);
$b = $a;
var_dump($a, $b);
// resource(2, gd)
// resource(2, gd)