<input type='file' id="uploadBannerImage" onchange="readURL(this);" />

function readURL(input)
{
    document.getElementById("bannerImg").style.display = "block";

    if (input.files && input.files[0]) {
        var reader = new FileReader();

        reader.onload = function (e) {
            document.getElementById('bannerImg').src =  e.target.result;
        }

        reader.readAsDataURL(input.files[0]);
    }
}

bannerImage = document.getElementById('bannerImg');
imgData = getBase64Image(bannerImage);
localStorage.setItem("imgData", imgData);

function getBase64Image(img) {
    // Create an empty canvas element
    var canvas = document.createElement("canvas");
    canvas.width = img.width;
    canvas.height = img.height;

    // Copy the image contents to the canvas
    var ctx = canvas.getContext("2d");
    ctx.drawImage(img, 0, 0);

    // Get the data-URL formatted image
    // Firefox supports PNG and JPEG. You could check img.src to guess the
    // original format, but be aware the using "image/jpg" will re-encode the image.
    var dataURL = canvas.toDataURL("image/png");

    return dataURL.replace(/^data:image/(png|jpg);base64,/, "");
}

<img src="" id="tableBanner" />

var dataImage = localStorage.getItem('imgData');
bannerImg = document.getElementById('tableBanner');
bannerImg.src = "data:image/png;base64," + dataImage;