Reduce image by factor

gistfile1.php

<?php

/**
 * Reduce image by factor
 *
 * @param string $originalFile file path
 * @param string $destinationFile file path
 * @param int $factor
 * @return bool
 */
private function resizeImageByFactor($originalFile, $destinationFile, $factor = 2)
{
    // Get width and height of original image
    $imageData = getimagesize($originalFile);

    if (!$imageData) {
        return false;
    }

    $originalWidth = $imageData[0];
    $originalHeight = $imageData[1];

    $newHeight = round($originalHeight / $factor);
    $newWidth = round($originalWidth / $factor);

    // Load the image
    if ($imageData['mime'] === 'image/png') {
        $imageType = 'png';
        $originalImage = imagecreatefrompng($originalFile);
    }

    if ($imageData['mime'] === 'image/jpg' || $imageData['mime'] === 'image/jpeg') {
        $imageType = 'jpg';
        $originalImage = imagecreatefromjpeg($originalFile);
    }

    if ($imageData['mime'] === 'image/gif') {
        $imageType = 'gif';
        $originalImage = imagecreatefromgif($originalFile);
    }

    if (!isset($originalImage, $imageType)) {
        return false;
    }

    $smallerImage = imagecreatetruecolor($newWidth, $newHeight);
    $squareImage = imagecreatetruecolor($newWidth, $newHeight);

    // Save alpha!
    imagealphablending($squareImage, false);
    imagesavealpha($squareImage, true);
    $transparent = imagecolorallocatealpha($squareImage, 255, 255, 255, 127);
    imagefilledrectangle($squareImage, 0, 0, $newWidth, $newHeight, $transparent);
    imagealphablending($smallerImage, false);
    imagesavealpha($smallerImage, true);
    $transparent = imagecolorallocatealpha($smallerImage, 255, 255, 255, 127);
    imagefilledrectangle($smallerImage, 0, 0, $newWidth, $newHeight, $transparent);
    imagecopyresampled($smallerImage, $originalImage, 0, 0, 0, 0, $newWidth, $newHeight, $originalWidth, $originalHeight);

    // Copy Image
    imagecopyresampled($squareImage, $smallerImage, 0, 0, 0, 0, $newWidth, $newHeight, $newWidth, $newHeight);

    // Save the smaller image FILE if destination file given
    if($imageType === "jpg") {
        imagejpeg($squareImage, $destinationFile, 100);
    }

    if($imageType === 'gif') {
        imagegif($squareImage, $destinationFile);
    }

    if($imageType === 'png') {
        imagepng($squareImage, $destinationFile, 9);
    }

    imagedestroy($originalImage);
    imagedestroy($smallerImage);
    imagedestroy($squareImage);

    return true;
}