<a href="http://www.livewetter.org/"><img id="wetterbild1" width="200" height="150" /></a> <br>
   <a href="http://www.livewetter.org/"><img id="wetterbild2" width="200" height="150"  /></a>
    <script>
        function adjVal(v) {
            if (v < 10) v = "0" + v;
            return v;
        }
        function getUrls(now) {
            var now = new Date();
            var fullYear = now.getUTCFullYear(),
                year = fullYear - 2000;
            var month = adjVal(now.getUTCMonth() + 1);
            var date = adjVal(now.getUTCDate());
            var hour = now.getUTCHours();
            var hour6 = adjVal(Math.floor(hour / 6) * 6);
            hour = adjVal(hour);
            var url1 = "http://www.zamg.ac.at/fix/wetter/bodenkarte/"
                + fullYear + "/" + month + "/" + date + "/BK_BodAna_Sat_"
                + year + month + date + hour6 + "00.png";
                //+ year + month + date + "0000.png";
            var url2 = "http://www.zamg.ac.at/dyn/pictures/Hsatimg/H"
                + year + month + date + hour + "00.gif";
                //+ year + month + date + "0000.gif";
            return [url1, url2];
        }
        document.getElementById("wetterbild1").addEventListener("error", function () {
            if (zaehler1 < 10) {
                now1.setUTCHours(now1.getUTCHours() - 6);
                this.src = getUrls(now1)[0];
                zaehler1++;
            }
        });
        document.getElementById("wetterbild2").addEventListener("error", function () {
            if (zaehler2 < 10) {
                now2.setHours(now2.getHours() - 1);
                this.src = getUrls(now2)[1];
                zaehler2++;
            }
        });
        var now1 = new Date(), now2 = new Date(),
            zaehler1 = 0, zaehler2 = 0;
        var urls = getUrls(now1);
        document.getElementById("wetterbild1").src = urls[0];
        document.getElementById("wetterbild2").src = urls[1];
    </script>