gistfile1.php

<?php

class DynamicImage {
	
	/**
	 * @var HttpRequest
	 */
	private $req;
	/**
	 * @var File
	 */
	private $file;
	private $status;
	private $width;
	private $height;
	
	function DynamicImage() {
		$this->req    = &HttpRequest::getInstance();
		$this->file   = null;
		$this->status = false;
		$this->width  = 0;
		$this->height = 0;		
		$this->init();
	}
	
	function init() {
		
		$req = &$this->req;
		
		if ($path = $req->getParameter('im', null, PHPType::STR())) {
			
			$file = new File($path);
						
			if ($file->exists()) {
				$this->status = true;
				$this->file = &$file;
			}
			
			$this->width  = $req->getParameter('w', 100, PHPType::INT());
			$this->height = $req->getParameter('h', 100, PHPType::INT());
			
		}
		
	}
	
	function write() {
		
		if ($this->file && $this->status) {
			
			$info 	 		= getimagesize($this->file->getAbsolutePath());
			$extHandler 	= $this->getImageHandler($info['mime']);			
			$imageFunction  = 'imagecreatefrom' . $extHandler;
			$imageHandler   = 'image' . $extHandler;
			
			$image = $imageFunction($this->file->getAbsolutePath());

			if (function_exists('imagecreatetruecolor')){
				$thumb = imagecreatetruecolor($this->width, $this->height);
			} else {
				$thumb = imagecreate($this->width, $this->height);
			}
			
			imagecopyresized($thumb, $image, 0, 0, 0, 0, $this->width, $this->height, ImageSX($image), ImageSY($image));
			//$image_handler($thumb, '', 100);
			header('Content-type:image/' . $extHandler); 
		    header('Cache-Control: no-store, no-cache, must-revalidate'); 
		    header('Cache-Control: post-check=0, pre-check=0', false); 
			$imageHandler($thumb);
			imagedestroy($thumb);
			
		}
		
	}
	
	function getImageHandler($mime) {
		
		$info['png']  = array('image/png', 'image/x-png');
		$info['jpeg'] = array('image/pjpeg', 'image/jpeg');
		$info['gif']  = array('image/gif');
		
		foreach($info as $key=>$value){
			if (in_array($mime, $info[$key])){
				return $key;
			}
		}
		
	}
	
}

//usage
$di = new DynamicImage();
$di->write();

?>