How To Load Image Under Header Tag In Django?

all other images that are under "img" tag are loading successfully, but i have one image under "header" tag, like this:

<header class="pt100 pb100 parallax-window-2" data-parallax="scroll" data-speed="0.5" data-image-src="{% static 'assets/img/serv.jpg' %}" data-positionY="1000">

but this image is not loading, can anybody suggest, how to overcome this issue?

when i run the raw template in browser, the image loads without any issue, but unable to making it work with django!

fixed this issue by adding an "style" tag and remove the

data-image-src="{% static 'assets/img/serv.jpg' %}"

as django was not able to load the image, when we use data-image-src like syntax, i still don't get it, why it was not working with django, if anybody knows the reason, please let me know.

<header class="pt100 pb100 parallax-window-2" data-parallax="scroll" data-speed="0.5" data-positionY="1000"  style="background-image: url({% static 'assets/img/serv.jpg' %}); background-position: center;">