Hi,
So it took me a bit to find a solution, and you are still going to need to tweak this to get it to work…
Your theme has three different break points, so you need to specify CSS for each. Below is the example code I used. You can adjust the height up and down as needed.
@media only screen and (max-width: 1200px) {
.gch-header-image-inner img {
width: 100% ;
height: auto;
}
}
@media only screen and (max-width: 960px) {
.gch-header-image-inner img {
width: auto !important;
max-width: inherit;
height: 400px;
}
}
@media only screen and (max-width: 800px) {
.gch-header-image-inner img {
width: auto !important;
max-width: inherit;
height: 300px;
}
}
Note that on smaller screens, you will only see the left hand side of the image, the rest will flow off the side of the screen. On way to counter this effect is take a completely different approach using the Header Raw Content option with background images. This takes a bit more HTML and CSS. If you would like to see a code snippet of that I can dig one up, but otherwise this is about all the free support I can give on this.
I hope this helps, good luck.
Nick