By default, we fix image heights to When the viewport is narrow enough, mobile CSS takes over and forces images to fill 100% of the page width instead.
height=315
, and let the width
be calculated proportionally once the image loads. We therefore ignore the actual image size. This is done to:- prevent reflows as the page loads images and can determine their actual sizes, especially is the user opens the page at a given ID in the middle of the page
- create a more uniform media experience by default, unless a custom image size is actually needed e.g. if the image needs to be larger
Here's a very long test image: