Aspect ratio
Aspect ratio expresses the proportion between the width and height of an image, video or container, such as 16:9 or 1:1. It helps define composition and available space
What it means, how it is used and where it comes up, with its related concepts.
What it is and how it works
When content and container have different proportions, the content may be cropped, distorted or shown in full with empty space remaining. The choice depends on which information must be preserved. Reserving dimensions before media loads helps reduce layout shifts, but should be consistent with the final presentation.