JSFiddle - React, Tailwind, and code Playground

HTML

<div style="background-color: black">
    <img id="teste" />
</div>
<button id="btnLoad">load img</button>

JavaScript

var img = document.querySelector("#teste");
var btnLoad = document.querySelector("#btnLoad");

function buscarImagem() {

    var oReq = new XMLHttpRequest();
    oReq.open("GET", "http://fiddle.jshell.net/img/logo.png", true);
    oReq.responseType = "arraybuffer";

    oReq.onload = function (oEvent) {

        var arrayBuffer = oReq.response; // Note: not oReq.responseText
        var binaryString = '';

        if (arrayBuffer) {

            var byteArray = new Uint8Array(arrayBuffer);

            for (var i = 0; i < byteArray.byteLength; i++) {


alert('i = ' + byteArray.byteLength);

                binaryString += String.fromCharCode(byteArray[i]); //extracting the bytes

            }

            var base64 = window.btoa(binaryString); //creating base64 string


            img.src = "data:image/png;base64," + base64; //creating a base64 uri

        }
    };

    oReq.send(null);

}

btnLoad.onclick = buscarImagem;