Just use the og:image multiple times.
See Example below:
<meta property='og:url' content='http://www.web-technology-experts-notes.in/' />
<meta property='og:title' content='Web technology experts notes' />
<meta property='og:description' content='Web technology experts notes' />
<meta property='og:site_name' content='http://www.web-technology-experts-notes.in/' />
<meta property='og:type' content='website' />
<meta property='og:image' content='http://img.youtube.com/vi/EwznozFWcTs/mqdefault.jpg' />
<meta property='og:image' content='http://img.youtube.com/vi/Dg_IN8jAoag/mqdefault.jpg' />
<meta property='og:image' content='http://img.youtube.com/vi/LauTDyg2ovg/mqdefault.jpg' />
<meta property='og:image' content='http://img.youtube.com/vi/1WOO2kT-ryE/mqdefault.jpg' />