400x400

400x400 denotes a digital image size where both width and height are 400 pixels, producing a square with an aspect ratio of 1:1. The image contains 160,000 pixels in total, and its diagonal length is approximately 565.7 pixels. This square format is commonly used for assets that require equal dimensions on all sides, such as profile photos and square thumbnails.

In computing and web design, 400x400 is a common canvas size for avatars, gallery previews, icons, and various user interface elements. When embedding in webpages, CSS can fix the display size with width: 400px; height: 400px;, or use object-fit to preserve content. If maintaining aspect ratio is important, designers typically set a single dimension and adjust the other automatically.

Practical notes include that downscaling from larger sources to 400x400 can reduce detail and may introduce artifacts, while upscaling a smaller image can appear blurred. For print, pixel dimensions are not the sole consideration; dots per inch (DPI) affects print size and quality. Common file formats for 400x400 images include PNG and JPEG, with SVG used for vector graphics that can be scaled to 400x400 without loss of quality.