Magento 2 product image on product page load slowly

Question

I'm using Magento 2.2.3 with a theme based on luma theme, no change did to the product images gallery. Images have all low size, even so, it takes like 3-4 seconds to load the first image. I have tried the Xumulus extension, but is not really a great choice, as it loads the image first, but delay all the js, so for a few seconds can't do pretty much nothing, like adding to cart.

Answer 1

Run this cli command

php bin/magento setup:static-content:deploy