A good website loads quickly. Before uploading your images to your website you should resize them to a suitable size and optimise them to save on download times for you site's viewers.
Lost sales due to slow loading websites
If your site loads slowly, you WILL lose some of your site's visitors. In the case of online stores, that means potential (often probable) lost sales.
Free image compression tools
Imagify is a great tool for compressing your images before you upload them. You can compress images for free, or sign up for even more useful features. Try it out today at https://imagify.io/optimizer