CSS display:none

Reference Image. There is another section on this page with two other images. It is hidden. Inspect the page with devtools to see the impact. See screencap below of the network panel from this project (minus the screencap). You will see that the browser loads the elements and the images and any code element hidden this way. So building multiple "layouts" in a CMS template and using conditionals is affected the same way. At least responsive image gen happens.