This is a simple piece of code, that can be incorporated into an iframe so that you can transition between two images using a swiper bar.
Many sites have something like this, to show a scene before - and after - some event. But this is mine. And now it's yours, since you only need to include your URLs in the iframe path.
Images courtesy of PaintAThousandWords.com/.
You simply need to include this code in your web page, with accessible URLs to your two images in place of the dots.
<iframe width="850" height="640" frameborder="0" src="//marquisdegeek.com/swiper/embed.htm?image1=...&image2=...">e.g.
<iframe width="850" height="640" frameborder="0" src="//marquisdegeek.com/swiper/embed.htm?image1=http://i1308.photobucket.com/albums/s603/paintathousandwords/150_zps01fbc8d5.jpg&image2=http://i1308.photobucket.com/albums/s603/paintathousandwords/771_zps76de7caf.jpg">