Images in blog posts being cropped on mobile instead of scaling down

I’m hoping someone can help me out with a plugin or something I can use, the images in the blog posts are fine on desktop, but on mobile they crop instead of just scaling down. The site’s istoptheworld.com/blog-2

I’m sure I can’t be the only one who’d want to prevent cropping instead of scaling, but I can’t seem to find a plugin that’ll do it.