Second image doesn't display on page.

@zombiedad Won’t show up where? It doesn’t show up directly in the frontend. You need to use it in your own way. Check this.

Hello,
it also doesn’t show up on my theme (using “Screenr”).
I pasted the first two codes snippets from the above linked GitHub-Wiki, but it didn’t work…first one showed the code in the frontend, second one somehow displayed strange text from somewhere else..

Here is the code which of the original template which I want to replace.

<?php
    if ( has_post_thumbnail() ) {
    the_post_thumbnail( 'screenr-service-small' );
  }
 ?>

Maybe I have to use another code here than the one from the wiki?
Please help…