Hi constantinos.rokkos,
Thanks for reaching to us and your patience.
Our theme doesn’t control product images size. It is controlled by WooCommerce plugin. You can configure it in Appearance -> Customize -> WooCommerce -> Product images.
I kindly recommend you preparing images with titles you want before uploading them to your media library using the graphic editor (Photoshop or any other) to have a nice-looking grid.
Or please add the following Custom CSS code to Theme Settings > Custom CSS > Global Custom CSS:
.single-product .woocommerce-product-gallery img {
width: auto;
}
Regards,