How to Create Thumbnail Images of uploaded image using PHP

This tutorial will describe how to create thumbnail images on the fly using PHP while uploading a image. With uploaded of single image you can create different thumbnail with different size of same Image. Here you will Learn how to process a images and create their thumbnails.

System Requirements:

Work for PHP only.
GD library must be installed which you can check with phpinfo() with version of >=GD 2.0.1
Uploading image size should be less than 2MB but if you want to increase then increase the value of "upload_max_filesize", "post_max_size" from php.ini

Code Snippets

   function resize($width, $height, $imageName,$extension) {
        if(empty($width) || empty($height) || empty($imageName) || empty($extension)){
            die('Required parameter is missing');
        }
        $docRoot = getenv("DOCUMENT_ROOT");
        
        /* Get original image x y */
        $tmpNM = $_FILES['files']['tmp_name'];
        
        list($w, $h) = getimagesize($_FILES['files']['tmp_name']);
        /* calculate new image size with ratio */
        $ratio = max($width / $w, $height / $h);
        $h = ceil($height / $ratio);
        $x = ($w - $width / $ratio) / 2;
        $w = ceil($width / $ratio);
        /* new file name */
        $path = $docRoot . '/images/thumb/' . $imageName;

        /* read binary data from image file */
        $imgString = file_get_contents($_FILES['files']['tmp_name']);
        /* create image from string */
        $image = imagecreatefromstring($imgString);
        $tmp = imagecreatetruecolor($width, $height);
        imagecopyresampled($tmp, $image, 0, 0, $x, 0, $width, $height, $w, $h);
        $fileTypes = array('jpg', 'jpeg', 'jpe', 'png', 'bmp', 'gif'); // File extensions
        /* Save image */
        switch ($extension) {
            case 'jpg':
            case 'jpeg':
            case 'jpe':
                imagejpeg($tmp, $path, 100);
                break;
            case 'png':
                imagepng($tmp, $path,0);
                break;
            case 'gif':
                imagegif($tmp, $path, 100);
                break;
            case 'bmp':
                imagewbmp($tmp, $path);
                break;
            default:
                exit;
                break;
        }
        return $path;
        /* cleanup memory */
        imagedestroy($image);
        imagedestroy($tmp);
    }

This function is able to create multiple thumbnail with different sizes of uploaded images.

How to create thumbnail of 50pxX50px image?

    
    $w='50'; //New image width
    $h='50'; //New image height
    $imageName=$w.'_'.$h.'_'.$_FILES['files']['name']; //Uploaded file Name
    $imageExtensionArray = explode(".", $_FILES['files']['name']);
    $extension=$imageExtensionArray[1];
    $this->resize($w, $h,  "{$imageName}",$extension);

How to create thumbnail of 100pxX100px image?

$w='100'; //New image width
$h='100'; //New image height
$imageName=$w.'_'.$h.'_'.$_FILES['files']['name']; //Uploaded file Name
$imageExtensionArray = explode(".", $_FILES['files']['name']);
$extension=$imageExtensionArray[1];
$this->resize($w, $h,  "{$imageName}",$extension);