Adding JavaScript to Slideshow?
I ended up creating a regular view, not a slideshow. Then I used a variation on the code above to reshape the images. And I used CSS on the mini pager to turn it into the buttons that one would find in a typical slideshow. It turned out exactly how I wanted it. Although it took a lot of time and aggravation, I learned a bit more about about Drupal, JavaScript, and CSS. Plus, I can reuse the code again.

If anyone is interested, my final JavaScript code is below; there were a few minor problems with the code above that caused it to act wonky in certain resizing situations.

    function myFunction() {
      var x = document.getElementsByClassName("slide");


      for (i = 0; i &lt; x.length; i++) {
        var viewHeight = window.innerHeight;
        var viewWidth = window.innerWidth;
        var viewAspect = viewWidth / viewHeight;

        var imageHeight = x[i].height;
        var imageWidth = x[i].width;
        var imageAspect = imageWidth / imageHeight;


        if (imageAspect &lt; viewAspect) {
          x[i].style.height = viewHeight + "px";
          x[i].style.width = "auto";
          x[i].style.marginTop = - viewHeight/ 2 + "px";
          x[i].style.marginLeft = - x[i].width / 2 + "px";
        }
        else {
          x[i].style.width = viewWidth + "px";
          x[i].style.height = "auto";
          x[i].style.marginTop = - x[i].height / 2 + "px";
          x[i].style.marginLeft = - viewWidth / 2 + "px";       
        }
      }
    }

    window.onload = function() {
      myFunction();
    };

    window.onresize = function() {
        myFunction();
    };