I'm finding suggestions that I should be uniform in my product image sizes, but I don't have tons of control over image quality, I am subject to whatever the manufacturer sends me. So I get an image that's 338 x 600 and I'm seeing my base image should be around 1000 x 1000, but there is no way for me to post a quality image of that size with the original file. Even if I try to just size it perfectly to fit my theme (515 x 515), it doesn't look as good as the original 338 x 600.
Example (first image is original, second is 515 x 515):
https://www.craftdirect.com/escape-to-nature-stamp-set-summer-adventure-lori-whitlock-echo-park.html
It seems silly that I would sacrifice image quality just for the sake of uniformity. Does anybody have any wisdom that they could impart? Am I totally wrong on this, or is there some solution I'm not seeing?