index.js

var randomNumber1 = Math.floor(Math.random()*6) + 1;
var randomDiceImg1 = "dice" + randomNumber1 + ".png" ; 
var randomDiceSrc1 = "images/" + randomDiceImg1 ; 
var image1 = document.querySelectorAll("img")[0];
image1.setAttribute("src", randomDiceSrc1);

var randomNumber2 = Math.floor(Math.random()*6) + 1;
var randomDiceImg2 = "dice" + randomNumber2 + ".png";
var randomDiceSrc2 = "images/" + randomDiceImg2;
var image2 = document.querySelectorAll("img")[1];
image2.setAttribute("src", randomDiceSrc2);

if (randomNumber1>randomNumber2){
    document.querySelector("h1").innerHTML="Play 1 wins!";
} else if (randomNumber1<randomNumber2){
    document.querySelector("h1").innerHTML="Play 2 wins!";
} else {
    document.querySelector("h1").innerHTML="Draw!";
}