Mine

<?php

$dialog = new GtkFileChooserDialog("File Save", null, Gtk::FILE_CHOOSER_ACTION_SELECT_FOLDER, array(Gtk::STOCK_OK, Gtk::RESPONSE_OK), null);
$dialog->show_all();
if ($dialog->run() == Gtk::RESPONSE_OK) {
	$selected_file = $dialog->get_filename();
	echo "selected_file = $selected_file\n";
	$progress_dialog = new ShowProgress(); // note 1
	$idle_id = Gtk::idle_add($progress_dialog,'pulse');
	$search = new ImageSearch();
	$search->search($selected_file);
	$progress_dialog->dialog->destroy(); // done. close the dialog box.
	Gtk::idle_remove($idle_id);
}
$dialog->destroy();

class ShowProgress { // note 1

	public $progress_bar;
	public $dialog;

	function ShowProgress() {
		$dialog = new GtkDialog('Scanning in progress...', null, Gtk::DIALOG_MODAL); // create a new dialog
		$top_area = $dialog->vbox;
		$top_area->pack_start(new GtkLabel('Please hold on while processing directory...'));
		$this->progress_bar = new GtkProgressBar();
		$this->progress_bar->set_orientation(Gtk::PROGRESS_LEFT_TO_RIGHT);
		$top_area->pack_start($this->progress_bar, 0, 0);
		$dialog->set_has_separator(false);
		$dialog->show_all(); // show the dialog
		$this->dialog = $dialog; // keep a copy of the dialog ID
	}
	
	public function pulse(){
		$this->progress_bar->pulse(); 
		return true;
	}
}

class ImageSearch{
	
	protected $search = true;
	
	public function search($path){
		$this->search = true;
		$found = array();
		if (!$this->gather($path,$found)) {
			return false;
		}else{
			return $found;
		}
	}
	
	public function cancel(){
		$this->search = false;
	}
	
	protected function gather($path,&$found){
		$dir = new DirectoryIterator($path);
		foreach ($dir as $file){
			while(Gtk::events_pending()) Gtk::main_iteration();
			if ($file->isFile() & !$file->isDot() & !$file->isDir() & $file->isReadable()) {
				echo $file->getPath().DIRECTORY_SEPARATOR.$file->getFilename()."\n";
				$data = getimagesize($file->getPath().DIRECTORY_SEPARATOR.$file->getFilename());
				if ($data > 0) {
					$found[] = array($file->getFilename(),$file->getPath());
				}
			}
			if (!$file->isDot() & $file->isDir()) {
				$this->gather($file->getPath().DIRECTORY_SEPARATOR.$file->getFilename(),$found);
			}
			if ($this->search == false) {
				return false;
			}
		}
		return true;
	}
	
}

?>