<?php
$image_dir = '';
$dir = new DirectoryIterator(dirname(__FILE__).DIRECTORY_SEPARATOR.$image_dir);
foreach ($dir as $fileinfo) {
    if ($fileinfo->isFile() && in_array($fileinfo->getExtension(),array('jpg','png'))) { ?>
        <a href="<?php echo $image_dir.$fileinfo->getBasename(); ?>"><img width="625" src="<?php echo $image_dir.$fileinfo->getBasename(); ?>" /></a>
  <?php  } 
  }
?>
