How do I make the thumbnail of products not enlarged?

The thumbnail of the photos for the products are super enlarged. How can I fix this?

The actual image is probably enlarged, try my workaround below as the uploaded images in your image storage are already resized so when you copy that URL and load it as a thumbnail, that will show in a small size instead of a large one.

Please check my screencast below.

I hope that helps. Let us know if you have any questions or if you need further assistance.