I have problem with blurry images as well. I am using Custom Community Pro theme.
I’ve noticed that for example I have Single Product Image size set to 300X300. (in WC Settings >> Catalog >> Image Options), but it is displayed as 330×330 instead of 300×300. I would think that my images are blurry because they are resized to 300X300, but stretched to 330×330. The same problem with Catalog Images and Product Thumbnails.
Any suggestions how to fix this?