Image resolution in product grid degrades

[mellex]

Ok - so. Product photos are square and a good resolution (2100x2100 and 300 dpi which is 7x7 inches). On homepage, in the "featured collections" section, images look fine. Click through to a collection and images in the "product grid" degrade and are blurry (text on product is particularly blurry).

I don't see why this happens or what a fix might be...

Origin theme.