Crop Image and Display it using PHP

$filename= "my_picture.jpg";
list($w, $h, $type, $attr) = getimagesize($filename);
$src_im = imagecreatefromjpeg($filename);
 
$src_x = '0';   // begin x
$src_y = '0';   // begin y
$src_w = '100'; // width
$src_h = '100'; // height
$dst_x = '0';   // destination x
$dst_y = '0';   // destination y
 
$dst_im = imagecreatetruecolor($src_w, $src_h);
$white = imagecolorallocate($dst_im, 255, 255, 255);
imagefill($dst_im, 0, 0, $white);
 
imagecopy($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h);
 
header("Content-type: image/png");
imagepng($dst_im);
imagedestroy($dst_im);