You will need to do some custom CSS. Here is an example for your first widget:
<span style="text-align:center;"><div class="post-thumbnail" style="margin-top:10px; padding:6px; display:block; background:none;border:none;">
<img class="center" style="background-color:#f6f6f6; border: 1px solid #d2d2d2; padding:6px;" src="http://kazyansky.com/wp-content/uploads/2014/05/Yakov_home3.jpg" alt="Yakov Kazyansky">
</div><h3>Yakov Kazyansky</h3>
</span>
I wrapped your content in a span container with an inline style, then I also added display:block; to the post-thumbnail div container. I also removed the styling for the post-thumbnail container because it expanded in width showing a lot more background colour, so I removed it from that container as you can see background: none; border: none; and then re-added the styling to the actual image with an inline style.
Sorry for the complicated styling…at some point I need to redo the theme and bring it up to date with easier customization.
Thank you so much for your help!