Typo3 Crop images (square) 40px x 40px

$gbobj=t3lib_div::makeInstance('tslib_gifBuilder');
$img=$gbobj->imageMagickConvert($file, 'gif', 40, 40,NULL,NULL, $conf);
$newfile = $img[3];

the function 

/**

* Make a thumb file with specified w/h - without constrains like proportions w/h

*

*

*/
public function makeSquareImage($file,$extension,$wh){
  $gbobj=t3lib_div::makeInstance('tslib_gifBuilder');
  $img=$gbobj->imageMagickConvert($file, $extension, $wh, $wh);
  $newfile = $img[3];
  return $newfile; 
}