How can I add an image to the background of the forum?

For IPS4, you will need to add the following CSS to the custom.css file of your theme. Please be sure to duplicate the default theme before making any edits so this way if something goes wrong you have a backup of the default theme that you know is working

body {
    background: url('*image url*'); /*Replace *image url* with actuall URL to image*/
}

#ipsLayout_header header {
    background-color: transparent;
}

 

Many thanks