gaussian blur in one sector of the image PHP

image.php

<?php

$loadFile = 'https://c1.staticflickr.com/5/4094/4809804115_40f52c8f25_b.jpg';

$image = imagecreatefromstring(file_get_contents($loadFile));


if ($image !== false) {
    $face = imagecrop($image, ['x' => 152, 'y' => 568, 'width' => 199, 'height' => 199]);

    /* Get original image size */
    $w = 199;
    $h = 199;

    /* Create array with width and height of down sized images */
    $size = ['sm' => ['w' => intval($w / 4), 'h' => intval($h / 4)],
             'md' => ['w' => intval($w / 2), 'h' => intval($h / 2)],
    ];

    /* Scale by 25% and apply Gaussian blur */
    $sm = imagecreatetruecolor($size['sm']['w'], $size['sm']['h']);
    imagecopyresampled($sm, $face, 0, 0, 0, 0, $size['sm']['w'], $size['sm']['h'], $w, $h);

    for ($x = 1; $x <= 2; $x++) { //Should be higher than 1
        imagefilter($sm, IMG_FILTER_GAUSSIAN_BLUR, 999);
    }

    imagefilter($sm, IMG_FILTER_SMOOTH, 99);
    imagefilter($sm, IMG_FILTER_BRIGHTNESS, 10);

    /* Scale result by 200% and blur again */
    $md = imagecreatetruecolor($size['md']['w'], $size['md']['h']);
    imagecopyresampled($md, $sm, 0, 0, 0, 0, $size['md']['w'], $size['md']['h'], $size['sm']['w'], $size['sm']['h']);
    imagedestroy($sm);

    for ($x = 1; $x <= 1; $x++) { //Should be higher than 1
        imagefilter($md, IMG_FILTER_GAUSSIAN_BLUR, 999);
    }

    imagefilter($md, IMG_FILTER_SMOOTH, 99);
    imagefilter($md, IMG_FILTER_BRIGHTNESS, 10);

    /* Scale result back to original size */
    imagecopyresampled($face, $md, 0, 0, 0, 0, $w, $h, $size['md']['w'], $size['md']['h']);

    imagecopymerge($image, $face, 152, 568, 0, 0, 199, 199, 100);


    imagepng($face, 'face.png');
    imagepng($image, 'image.png');
    imagedestroy($face);
    imagedestroy($image);
} else {
    echo 'An error occurred.';
}