Works easy enough

I did not like that the images just switched without transition so I added some javscript to make that happen.
on lines 105 to 113 added:

.stop(true,true).hide().fadeIn();

so it should look like this

      mainImage
        .attr("data-ind", ind)
        .attr("src", med)
        .attr("srcset", med)
        .attr("width", width)
        .attr("height", height)
        .attr("data-hq", hq)
        .attr("data-w", hqw)
        .attr("data-h", hqh)
        .stop(true,true).hide().fadeIn();