How can i get 100% image size zoom?

Hi i’ve installed your wonderful plugin but i would like to know if it’s possibile to zoom the image to their full size. In my case i notice that the max possible size is about 60% of the image real dimensions.
Here is the link: https://www.leonardoscagli.it/prodotto/suspension-xl-001/
You can see that the first image (smaller than the other) is shown at its full size while the following images are being resized as i said earlier.

Thank you, Filippo.