How can I exclude an image from zooming?

It is possible to exclude desired images from zooming. However, it's not something that can be done through the app preference page for now; it needs to be done through your product templates. So, if you're familiar with liquid coding, you could get that effect by editing a few lines of liquid from your product templates.

You can set the CSS class  incubate-ignored-image in the HTML if you want to prevent an image to be zoomed in.

Cool Image Magnifier will ignore any image with the CSS class incubate-ignored-image, so adding that CSS class to the images in that template will make the loupe not zoom those images and let the customisation work as intended.