so, i am trying to customise my header-panel! i want add background image insted of background color!! inside my _theme.less file

     .page-header {
.panel.wrapper {
position: fixed; width: 100%; height: 100px; z-index: 5;
.lib-css(background-color, @white);
}


}

this code is working fine! but i want to add image instead of that color!! what i exactly need to do?

     .page-header {

and create a folder custom inside pub/media of magento installation and place your image as background-image.png. You can change the name of the folder and file and edit that in above code as well.