Thumbnail Images Not Aligning Properly

I have created three video pages using shortcode. Two of the pages are aligning the thumbnails in a downward diagonal pattern. Can I fix this to display them next to each other on horizontal rows? Thank you.

Here is a page where they are diagonal: http://nhlshout.com/nhlshout/?page_id=7739

Here is how I want them: http://nhlshout.com/nhlshout/?page_id=7652

The plugin is set for left justified.

Thank you.

http://wordpress.org/plugins/youtube-simplegallery/