Help with images being far too big

My wordpress theme has some images that are appearing way over-sized, but I cannot find the CSS or anywhere to fix it.

Would anyone offer some advice?

The site is here
(it’s in testing)

I’d love all those product images to be a fraction of their current size. The theme uses them as featured images, so there is no way to adjust the size when actually inserting them–I’ve tried.
The theme is “The Morning After”.

Much appreciated