Recommended Image Sizes using Responsive Classic?

What are the recommended image sizes for Zen Cart v1.5.5a using Responsive Classic?

The recommendations are no different for the responsive template versus a standard template
You have a choice - one you can create small med & lrg images
https://www.zen-cart.com/content.php?223-image-preparation-how-to

Or you can use image handler(a plugin) and only require your large image as it will create the others

Thanks! Although the recommendations may be no different, I'm still stuck because I can't find where anyone is actually recommending specific image sizes.
So I'm wondering if someone would make such a suggestion or provide a link to where this has already been discussed?

For a large image staying at about 640x480 is prudent and the byte size in the area of 100k

Zean:

What are the recommended image sizes for Zen Cart v1.5.5a using Responsive Classic?

There aren't any recommended image sizes per se. This will differ on a per site basis. However Google always provides lots of best-practice guides.