Images are not downloaded to your server. It's goes to viewers browser directly from Facebook's Server. As a result you save hosting space and bandwidth and your user gets fast page load. No more hosting your images on your own server. Use the servers of Facebook instead and show them in your site.
- Albums from Pages that you have administrative access to.
- Your personal albums
- For any other Pages/Profile (for example your clients) The owner or someone with admin access to the page will have to generate the access token
2. Facebook Groups (Facebook doesn't allow that)