Layout question

I have an examples section on my site, The gallery layout is done using Liquid Gallery, and I have used Vimeo Pop and Youtube pop to generate the lightboxs for the videos. I like these as I don’t have to create separate thumbnails.

There is one video which can’t be on vimeo for the time being so there is a local copy. To generate the lightbox I am using Topbox. But this needs a separate thumbnail.

What I am trying to do is find a way of generating (preferably automatically) a thumbnail that will be the same size as the rest of the pictures in the gallery. A play icon in the middle would be great so it matches the rest. Any thoughts greatly received.