Incorporating OOP in existing PHP
class ImageData {
  private $count;
  private $dirArray;

  public function __construct() {
    $count = 0;
    $dir = "panos/thumbs";
    $dirCon = opendir($dir);

    while ($name = readdir($dirCon)){
      if (strtolower(substr($name, -3)) == "jpg"){
        $dirArray[]= $name;
      }
    }

    sort($dirArray);
    $count= count($dirArray);

    closedir($dirCon);
  }

  public function getCount(){
    return $this->count;
  }

  public function getArray(){
    return $this->dirArray;
  }

}

$imageData = new ImageData();
$count = $imageData->getCount();
$data = $imageData->getArray();

class ImageData {
    protected $count = 0;
    protected $dir = null;
    protected $dirArray = null;

    public function __construct( $dir = 'panos/thumbs') {
        $this->dir = $dir;
    }

    public function getCount(){

       if ( is_array($this->dirArray) ){
           $this->initialize();
       }

       return $this->count;
    }

    public function getArray(){

       if ( is_array($this->dirArray) ){
           $this->initialize();
       }

       return $this->dirArray;
    }

    protected function initialize(){

       $this->dirArray = $this->findImages();

       sort($this->dirArray);
       $this->count = count($dirArray);

    }

    protected function findImages( $extensions = array('jpg') ){

       $files = array();
       $dirCon = opendir($this->dir);

       while ($name = readdir($dirCon)){
           $current = strtolower(substr($foo, strrpos($foo, '.')+1));
           if ( in_array( $current, $extensions ) ){
               $files[] = $name;
           }
       }

       closedir($dirCon);
       return $files
    }

}