Here is a possible solution the solution #3 on my comments to blubill's answer:
yourscript.php
========================
<?php
$dir = '/home/user/Pictures';
$file_display = array('jpg', 'jpeg', 'png', 'gif');
if (file_exists($dir) == false)
{
echo 'Directory "', $dir, '" not found!';
}
else
{
$dir_contents = scandir($dir);
foreach ($dir_contents as $file)
{
$file_type = strtolower(end(explode('.', $file)));
if ($file !== '.' && $file !== '..' && in_array($file_type, $file_display) == true)
{
$name = basename($file);
echo "<img src='img.php?name={$name}' />";
}
}
}
?>
img.php
========================
<?php
$name = $_GET['name'];
$mimes = array
(
'jpg' => 'image/jpg',
'jpeg' => 'image/jpg',
'gif' => 'image/gif',
'png' => 'image/png'
);
$ext = strtolower(end(explode('.', $name)));
$file = '/home/users/Pictures/'.$name;
header('content-type: '. $mimes[$ext]);
header('content-disposition: inline; filename="'.$name.'";');
readfile($file);
?>