Wallpapers and Screensavers

A desktop wallpaper is the background image displayed behind the icons and windows on a computer screen. It is usually a still picture — a photograph of nature, an animal, a landscape, a space scene or a graphic design — chosen to personalise the appearance of the desktop. Wallpapers are ordinary image files, most often in formats such as JPEG or PNG, and they look best when their pixel dimensions match the screen so the picture fills it without stretching or leaving blank edges.

Because screens come in many sizes and shapes, wallpapers are offered in a range of resolutions and aspect ratios. An image with too few pixels for a large display will appear soft or blocky when enlarged, so picking a version sized to the monitor keeps it sharp. The operating system provides options to centre, tile, stretch or fit the image, and themed collections group wallpapers by subject such as flowers, sports, science fiction, holidays or the night sky.

A screensaver is different from a wallpaper. It is a moving image or animation that activates after the computer has been idle for a set time. Screensavers were originally introduced to prevent a fixed image from being permanently burned into older cathode-ray-tube and plasma displays. On modern flat-panel screens that risk is largely gone, so screensavers now serve mainly decorative purposes or hide on-screen content while a user is away, and they may also trigger a password lock for privacy. Many wallpapers and screensavers are distributed free for personal use, though licence terms vary by source.

Frequently asked questions

What is the difference between a wallpaper and a screensaver?

A wallpaper is the still background image on the desktop, while a screensaver is a moving display that starts after the computer has been idle for a while.

Why should wallpaper resolution match the screen?

An image with too few pixels looks soft or blocky when enlarged, so a wallpaper sized to the monitor stays sharp and fills the screen cleanly.

Are screensavers still needed?

The original purpose of preventing screen burn-in matters little on modern flat panels, so screensavers are now mostly decorative or used to lock the screen for privacy.