private function save_image($img,$fullpath){
		$ch = curl_init($img);
		curl_setopt($ch, CURLOPT_HEADER, 0);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
		curl_setopt($ch, CURLOPT_BINARYTRANSFER,1);
		$rawdata=curl_exec($ch);
		curl_close ($ch);
		if(file_exists($fullpath)){
		  unlink($fullpath);
		}
		$fp = fopen($fullpath,'x');
		fwrite($fp, $rawdata);
		fclose($fp);
	}

Reference:

• http://stackoverflow.com/questions/6476212/save-image-from-url-with-curl-php
• http://edmondscommerce.github.io/php/curl/php-save-images-using-curl.html