Given an image object and effect, perform the effect on the file.
$image: An image object returned by image_load().
$effect: An image effect array.
TRUE on success. FALSE if unable to perform the image effect on the image.
function image_effect_apply($image, $effect) {
module_load_include('inc', 'image', 'image.effects');
$function = $effect['effect callback'];
return $function($image, $effect['data']);
}