I have built a Timeline using TimelineJS by [url removed, login to view]
It is integrated into Wordpress using the JSON API so that it fetches posts and they appear on the timeline.
I want the post featured image to render at full screen width (regardless of resolution) with the text positioned on top of the image.
This must be possible because it is being done here: [url removed, login to view]
I have analysed their code and they have been able to set their images as a background on a
They then use some CSS to make it fill the screen:
background-size: cover !important;
height: 100% !important;
min-height: 100% !important;
min-width: 100% !important;
width: 100% !important;