Size down zoomed product images to fit browser height
This customization will make the image fit on shorter screens when the zoom pop-up is used.
Example before:

Example after:

Allowing the customer to see the whole product without scrolling.
Code:
/* -- code to make zoomed images fit browser height -- */
.mfp-container img{max-width: 90vh;}
/* - end - */
Where do I add the code?
Use this link to learn where exactly to add this code snippet: