imagick

imagick is the native PHP extension to create and modify images using the ImageMagick library.

imagick is also known with the name Image Magick. It is able to convert between various formats, to edit, combine and optimize images.

<?php

$imagick = new Imagick($imagePath);

$imagick->resizeImage($width, $height, Imagick::FILTER_TRIANGLE , 0);

$width = $imagick->getImageWidth();
$height = $imagick->getImageHeight();

$newWidth = $width / 2;
$newHeight = $height / 2;

// crop image to half the middle of the image
$imagick->cropimage(
    $newWidth,
    $newHeight,
    ($width - $newWidth) / 2,
    ($height - $newHeight) / 2
);

// resize the picture to bigger size (4 times)
$imagick->scaleimage(
    $imagick->getImageWidth() * 4,
    $imagick->getImageHeight() * 4
);

// write the image to disk
$imagick->writeImage($imagePath.'.2');

?>

Documentation

See also PHP Imagick by Example and Installing Imagick for PHP on AWS EC2: Everything You Need to Know.

Related : Graphic Draw (GD), ImagickException, ImagickPixelException, PNG