let numerZdj = 0;
slajder();


function slajder() {
const img = document.getElementsByClassName("auto-galeria");


for ( let i = 0; i < img.length; i++) {
img[i].style.display = "none";
}
  
numerZdj++;

if (numerZdj > img.length) {
numerZdj = 1

}

img[numerZdj-1].style.display = "block";

setTimeout(slajder, 30000);
}