On theme panel, you can set the dimensions for images. There is also an option to enable WebP image compression for better performance. To enable WebP, go to “SEO & Performance” Tab.
NOTICE: WEBP is an important feature but if enabled, all the images on server will be also created in webp format, this means that you may need disk extra space on server if you have many many products. Also when you visit the page or product page (first time), it will be bit slow first time since webp images are created on the fly.