png images aren't resized by image box

Site URL: https://www.nationalinnovationgames.com/

Perhaps I'm doing something obviously wrong, but when I'm using png images they do not resize at all when viewing them on the live site. The preview shows them as fitting ok, but when I publish I only see the corner or part of the image, as if the entire thing has remained it's original size and exists 'off screen'.

And by size I don't mean MBs, it's the dimensions that don't adjust to fix the box or the page.

I've managed to get a couple to work by playing with the 'Design' of the image (specifically the 'Stack' option) but when I want to use a gallery then I don't have any other options.

Surely I don't have change the dimensions of every png to fit? Isn't that the point of Squarespace and using spacers to help resize images?? Any thoughts on what might be going wrong here?

Have you solved it yet? If no, Which images? We can check easier

You resize images that are in a box by using spacers.