gallery.js

function upDate(previewPic) {

    /* In this function you should 
    1) change the url for the background image of the div with the id = "image" 
    to the source file of the preview image
    
    2) Change the text  of the div with the id = "image" 
    to the alt text of the preview image 
    */
    old = document.getElementById("image").innerHTML
    document.getElementById("image").innerHTML = previewPic.alt
    document.getElementById("image").style.background = "url(" + previewPic.src + ")";

}
function unDo() {

    /* In this function you should 
    1) Update the url for the background image of the div with the id = "image" 
    back to the orginal-image.  You can use the css code to see what that original URL was
    
    2) Change the text  of the div with the id = "image" 
    back to the original text.  You can use the html code to see what that original text was
    */

    document.getElementById("image").innerHTML = old
    document.getElementById("image").style.background = "#8e68ff";

}