Ok..I also have left it at 1200×600 and set as uncropped. I ran the site on gtmetrix and I got a very low score. and the main reason is stated as below. All product images are having the same issue.. For example..

under “serve scaled images” section

https://<i removed domain>.com/wp-content/uploads/2018/10/Tanjore-painting-material-chalk-arabic-gum-600×766.jpg is resized in HTML or CSS from 600×766 to 214×273. Serving a scaled image could save 75.4KiB (87% reduction).

on the shop page I have 4 products in a row..and the page has a sidebar..
should I make further settings?