This Gumby's example site : http://tiltingpoint.com/#/
can control top red image when we change browser width and height.
I think it is done by the "full-screen" in the article tag.
<article id="panel-1"
class="panel"
full-screen=""
style="background-image:url("http://tiltingpoint.com/images/backgrounds/bg_panel_1.jpg");>
When we changed browwer height, this source was added height style. I understood it.
But I can't understand any more how does it work and can't find specific description.
Please tell me how to change image keep aspect according to changing browser width and height.
The only thing I can say is try adding this your css. This should make the image expand the full size of its container or parent element.
If that does not work you can do the same
These will work based on the size of the parent element. If you are trying to have it as a BG image I would try inserting into the html element or body element so it is not limited by a parent element that is small.