In the WordPress customizer you can select your preferred product gallery style.
Go to Single Product → Product Gallery to select the default gallery style. This will apply to all your products.
This gallery options only apply to desktop screen size. On mobiles the gallery will be always a carousel.
This is the default style. And you can choose between slide or fade transitions:
First image large and then 2 images on each row
All images in a single column
Choose the position of thumbnails. Valid only for the Carousel gallery style. On mobiles the thumbnails will become navigation dots.
Product Image Lightbox
Open the full size image in a lightbox
Product Image Zoom
Enabled zoom on mouse hover.
Override style on specific product
You can override the default gallery style on each product. On the product edit page go to Layout Settings and select your preferred Gallery Style