Image Resizing

Serving an image at the dimensions it is actually displayed at, rather than scaling a large file in the browser.

Generate a few widths and let srcset pick; a 2000px hero delivered to a 390px phone is wasted bandwidth on every visit.

Always set width and height attributes so the space is reserved before the file arrives.

Browser scaling costs both download time and rendering work on the device.

Reserved dimensions are also the simplest fix for layout shift caused by images.