[Plugin: Related Posts Thumbnails] How to adjust the column width of the related post

Since I upgraded to WP 3.4.1, I have been having issue with the column width of the related post thumbnail. Before the upgrade, the 4 related thumbnail used to be all lined up in 1 row, as the column width were tighter. Is there a way to adjust the column width of the related post thumbnail so that they can all lined up in 1 row vs. 2 rows as seen on this page?

http://www.escapetraveler.com/hiking-half-dome-yosemite-what-you-need-to-know/

http://wordpress.org/extend/plugins/related-posts-thumbnails/