Video poster images in Quickstart

I like the way the videos on the home page are set up in the quickstart. But, I can't figure out how to get a poster image to show up when I add a video. It works fine, but there is just that default gray box that the quickstart has.

Hi,
are you talking about homepage and module at the bottom ?
If yes, they uses K2 items
1) Upload screenshot from movie and add in "Image" tab
...remember to delete old one..
2) Add code of youtube move inside "Media" tab
3) Save

Sometimes it's better to add new K2 items in this same video category, you don't have to modify demo content, less time it takes.