Very good for image oriented sites. Is it possible to use a still image instead of video to show up on the top of the site?

Did you see the above posts?

You can add whatever you want, whether it's a picture or an animated picture.

Yes you add a still picture.
Just select the youtube setting to "No".
Upload the image you want to show to the "core/packages/yilmazcoverheader/img/" folder

I meant my post ;)