sd-webui-additional-networks/style.css

#additional_networks_cover_image,
#additional_networks_cover_image > .h-60,
#additional_networks_cover_image > .h-60 > div,
#additional_networks_cover_image > .h-60 > div > img
{
    height: 480px !important;
    max-height: 480px !important;
    min-height: 480px !important;
}