(PECL imagick 2.0.0)
Imagick::flipImage — Creates a vertical mirror image
Creates a vertical mirror image by reflecting the pixels around the central x-axis.
   Returns TRUE on success.
  
Throws ImagickException on error.
Example #1 Imagick::flipImage()
<?php
function flipImage($imagePath) {
    $imagick = new \Imagick(realpath($imagePath));
    $imagick->flipImage();
    header("Content-Type: image/jpg");
    echo $imagick->getImageBlob();
}
?>