When I inspect the element, it indicates galleria is using full size image instead of thumbnail.
Example from Galleria documentation is http://galleria.io/docs/getting_started/quick_start/
<div class="galleria">
<a href="/img/large1.jpg"><img src="/img/thumb1.jpg" data-title="My title" data-description="My description"></a>
<a href="/img/large2.jpg"><img src="/img/thumb2.jpg" data-title="Another title" data-description="My <em>HTML</em> description"></a>
</div>
My code is
<div class="galleria">
<a href="http://upload.wikimedia.org/wikipedia/commons/thumb/2/2f/3D_Schildersdoek.JPG/812px-3D_Schildersdoek.JPG">
<img src="http://upload.wikimedia.org/wikipedia/commons/thumb/2/2f/3D_Schildersdoek.JPG/220px-3D_Schildersdoek.JPG" alt=""/></a>
<a href="http://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Bitwa_pod_Grunwaldem_Muzeum_Narodowe_05.JPG/800px-Bitwa_pod_Grunwaldem_Muzeum_Narodowe_05.JPG">
<img src="http://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Bitwa_pod_Grunwaldem_Muzeum_Narodowe_05.JPG/300px-Bitwa_pod_Grunwaldem_Muzeum_Narodowe_05.JPG" alt=""/></a>
</div>
The link to jsfiddle for demo is http://jsfiddle.net/zain_aligent/EAVtM/4/
How can I make galleria use thumbnail images instead of full size images?