Header image only responsive larger, not smaller

I cannot get the header image to shrink, instead it just cuts off the sides on www.writersdrinkingcoffee.com for tablet or mobile Currently the image is larger than the suggested size, but the behavior is identical when it's altered to be exactly 1920x1080 I'm about to resort to making a child-theme and recoding, but it *says* it's responsive so I must be missing something