To display a list of files within a directory using PHP you need to use opendir() and readdir(). Below is a function that will return the list of files and remove the . and .. from the listing.

 
//full path of directory
$dir = "/var/www/images/";
 
function listFiles($dir){
 
//open directory and read its contents
if ($handle = opendir($dir)) {
while (false !== ($file = readdir($handle))) {
 
//only display filenames
if ($file != "." && $file != "..") {
echo "$file\n";
}
}
closedir($handle);
}
}
 

You might run into trouble trying to find the correct full path of the images. For example in a windows hosting environment the path could be  (c://blah/blah), in a Linux environment it could be (/var/www/blah/blah).

To find the exact path for your environment use phpinfo(). Once you have the php info look for the DOCUMENT_ROOT entry.