Change video thumbnail size on video page block

I am looking to enlarge the video thumbnails of the videos in Featured Video block and Todays Video blocks on home page and other pages with video blocks.

How do I edit the size of the thumbnails?

There is a setting for this in the module's section in the admin.  What you need to understand is that the existing thumbnails will stay the same since they were created before you change the size in the admin to a larger size.  If you look in the flash video module's files directory, you can see which ones are the thumbs.  If you want the old thumbs to be larger, you would need to download them locally; unless you are good with the GD or ImageMagick command line interface in shell.  You would then increase the size and then re-up them.  Or just live with the old ones being smaller.