Thumbnail sizes on related posts?

Hi All,

Hopefully this is simple. The thumbnails in the related posts section on my site are from a mix of embedded YouTube and local images. It seems the YouTube thumbnails are not the same dimension as those of local images and have additional black bars at top and bottom which is skewing the view.

How would I go about ensuring all the thumbnails in the related posts section are using the same dimensions?

The page I need help with: [log in to see the link]