Ultimate Shortcodes Blurry Image Slider

I am using the Ultimate Shortcodes Image Slider.
It’s great and I love having it on my homepage, except all of my images are slightly blurry/out of focus?!
It’s not because the images are being stretched, they’re high quality images and are actually quite big. They work fine displayed in blog posts and they show up perfectly in the carousel – which actually displays them larger than the slider does.

Can anyone help? It’s really not good having out of focus images but I don’t want to change to another plugin.

http://iconcept.mobi/jen2014/