Grazie, ma purtroppo qualcosa non va.

codice:
script>
const img1 = document.getElementById('img1')
const img2 = document.getElementById('img2')
    setInterval(()=>{
        img1.setAttribute('src','img1.jpg')
        img2.setAttribute('src','img2.jpg')
        console.log('caricata')
    },1000);

</script>

<h4>Cancello 1</h4>
<img src="http://192.168.1.216:8080/picture.jpg" class='imm' id="img1"/></img>
<h4>Cancello 2</h4>
<img src="http://192.168.1.215:8080/picture.jpg" class='imm' id='img2'/></img>
14:35:23.476 Uncaught TypeError: img1 is null
<anonymous> http://192.168.1.8/PPP/ref.php:67
ref.php:67:9

Dove la riga 67 è:
codice:
img1.setAttribute('src','img1.jpg')
Grazie
Sonia