"Thumbnail" size post for columns

I’m working on a website that has individual columns that show certain featured posts. When I embed media (photo, video) I want it to show only a thumbnail in these columns, while showing the full size on the main content section. Here is my current page: http://eliteathletic.com.previewdns.com/
If you scroll down you can see what I mean. If I want to have a video in the “news” section and the “featured” column, I need the size of the media to be different. Is this possible. What changes to I need to make to my featured column to have this work properly?