page header background image

Hi,

There is no option available in customizer to upload header banner image

You need to edit this using style.css as you done before.

You can add below CSS rules into Custom CSS Editor :

.page-banner {
    background: url(image/url/here);
}

Now change the image URL and save the changes.

Or open your style.css file in any text editor and Go to line no 841 and

find below line of code snippet:

.page-banner {
    padding: 80px 0;
    background: url(https://cmb.org.pk/wp-content/uploads/2016/04/slider-2-min-1300x400.jpg);
    border-bottom: 1px solid #eee;
}

and change background image URL here according your need.

Hope you understood.

Let us know for further assistance.

Thank You