I have tried a number of photo gallery components. I want somethings simple. The component should have only thumbnail and view photo. I found JoomGallery is fitted with my requirements!

http://extensions.joomla.org/component/option,com_mtree/task,viewlink/link_id,5481/Itemid,35/

That is simple and can view the full view image in an ajax window. That is good, reducing popup!