Untitled

 <?php
  
  $imgdir = 'testfolder/'; // the directory, where your images are stored
  $allowed_types = array('png','jpg','jpeg','gif'); // list of filetypes you want to show
  
  $dimg = opendir($imgdir);
  while($imgfile = readdir($dimg))
  {
   if(in_array(strtolower(substr($imgfile,-3)),$allowed_types))
   {
    $a_img[] = $imgfile;
    sort($a_img);
    reset ($a_img);
   }
  }
  
  $totimg = count($a_img); // total image number
   
  for($x=0; $x < $totimg; $x++)
  {
   $size = getimagesize($imgdir.'/'.$a_img[$x]);
  
   // do whatever
   $halfwidth = ceil($size[0]/2);
   $halfheight = ceil($size[1]/2);
	echo '<img src="'.$imgfile'" alt="" />'
  ?>