How do I prevent images from being enlarged?

[Tharsis]

I have an online store with prints of my artwork for sale. I wanted to stop my images from being magnified or zoomed in when they're clicked on. I read in an old post on this forum that resizing them to <640 x 640 at 72dpi and setting the image ratios to 1:1 would stop them from enlarging when clicked on. So I set all my images to 600x600 at 72dpi and the ratio is 1:1 - but they still enlarge when you click on them. They don't zoom in very much, but enough that the enlarged images look blurry and not something I want a customer to see.

What am I missing?

[Tharsis]

Where is the feature to disable zoom located? I have searched all over and I can't find that option. In "Item Details - Image Fit" There is "Crop" or "Scale" selections but neither makes any difference.

No matter what I've tried, when you hover over the image, the 'magnifying glass +' icon appears and you can click on the image to zoom in.