The size of the product images is an important part of putting together your online shopping store. The images need to be detailed enough for customers to see what they are purchasing and small enough for the best page speed.
Image Size
Straight to the answer. 1000px x 1000px is the ideal resolution to use for product images in your WooCommerce online store. If you have a lot of product images, you could reduce the size a little, however, you should use a minimum of 800px x 800px.
The absolute minimum should be 600px. WooCommerce defaults to showing the full product image in an initial width of 600px. The image used is the same resolution as it is uploaded as, with the full image resolution used when zooming in to view in detail.
If the products are particularly detailed, a larger resolution can be used, for example, 2000px by 2000px.
Image Ratio
Another part of image sizing is the ratio of the image. Generally, the image ratio is best as 1:1. It is more important to have consistency, so if you decide on using a 16:9 ratio or 3:2 ratio, ensure all of the product images use the same ratio.
Depending on your website’s theme and configuration, a ratio different to 1:1 may be more suitable. Usually, 1:1 ensures the product image has the most visibility without too much cropping. A wide or high image may still be displayed in a 1:1 ratio so it is best to use this ratio to begin with.
Summary
The best resolution for WooCommerce product images, with a balance of image detail and size for website speed, is 1000px by 1000px in a 1:1 ratio.