Layout issue on portfolio theme

Hello, I'm having a little issue reproducing the same layout as the articles already set on the portfolio theme and that are presented on the window frame of the first page of the theme.
I can't seem to have that "thumbnail" situated at the bottom of each article's window frame where what seems to be the "format" is shown (such as, "video", "quote" etc...)
Each time i'm creating a new article I don't see that showing up.
Any ideas why?
I hope I'm clear enough :/
You can see at http://tanguylagasse.com/ the difference between the new articles where that "thumbnail" is missing (2 first on the left hand side) and the original ones (all the others on the right handside and bottom)



Thank you very much!

Hi,

I've changed your frontpage settings, is it ok now?
Thumbnail in the article is taken from your featured image, did you set featured image for your new articles?