Yes, the Genesis Responsive Slider plugin (ver.0.9.2) is currently disabled that is why the wp real estate’s photo gallery looks good right now.
But if I enable the Genesis plugin, the wp-real estate slider will show its thumbnail similar in size as the featured image, but in pixelated form. Both (featured image and thumbnail images) will then change images (or slide) at the same time.
The theme I am using is Executive Pro (Genesis parent theme).