I hide all website footers by default, you wouldn't be surprised to know useless they usually are

    #footer, .footer { display: none !important; }

Userstyle to remove the image from this site:

    @-moz-document domain("niconiconi.neocities.org") {
        body {
            background-image: none !important;
        }
        #footer {
            display: none !important;
        }
    }