Hey Nishant,
Don’t know if a screenshot is really going show it.
Basically you have the primary image and the secondary images below the primary image. When selecting a variant the primary image changes (which is right). What this plugin does is makes it so you can have alternate secondary images for each variant, this is what isn’t working.
Eg. switch the colour to blue now every image is blue (the primary image and all images below it)
Right now the main image will change to blue but the images below will remain with whatever the original images were.
Are all images changing for you? I’ve tried multiple computers and multiple browsers and none seem to work.
WooCommerce demo: http://demo.royho.me/product/ship-your-idea-2/
Does that make sense?