Can’t Make Header Image Responsive

Hi There,

I have been using this theme which works really good for my website but have one issue with it. Well i am trying to put one custom image on the header section using “Header Background Image”. It is uploaded and works fine on Desktop but its not responsive image. Seems you have not set max 100% width for any image to be uploaded here thats why max part of the image is getting cut off from mobile or Tab devices.

I am not able to figure out to make it work for all devices, Can you suggest anything?

Thanks
Darren