Images used as computer wallpaper are usually raster graphics with the same size as the display resolution (for example 1024×768 pixels, or 1280×1024 pixels) in order to fill the whole background.
Many screen resolutions are proportional in a 4:3 ratio, so an image scaled to fit in a different-sized screen will still be the correct shape, although that scaling may impact quality. Common wallpaper resolutions are 800x600, 1024x768, 1280x1024 and 1600x1200.
Users with widescreen (16:9 or 16:10) monitors have different aspect ratio requirements for wallpaper, although images designed for standard (4:3) monitors can often be scaled or cropped to the correct shape without undue loss of quality.
Wallpapers are sometimes available in double-width versions (e.g. 2560×1024) for displaying on multi-monitor computers, where the image appears to fill two monitors.
Some display systems allow unconventionally-proportioned images (1:1, 2:1, or even 1:3) to be scaled without change of proportion, to fit the screen, whether it be 16:9 or 4:3. The image would be sized just large enough that one pair of edges touch the edges of the screen, but not all four, as this would unduly distort the image. In these cases, the system's "default" background color is visible around the other two sides of the image.
Another common option, particularly for images much smaller than the resolution of the display, is having the image displayed multiple times like a series of tiles. This avoids the distortion of scaling.
How do I change my wallpaper in Windows XP?
Find a new wallpaper you like and click on the appropriate link to download the resolution you want (e.g. 1600x1200). A new window will popup will show up which gives you the option to either download the image, or view it in your browser. Choose the last option. With the full image in your browser right-click on the image and select "Set as Background" from the popup menu. How do I change my wallpaper in Mac OS X?
Start by downloading a new wallpaper to your Desktop. Put this file in the 'Pictures' folder inside your Home Directory. Now open up the 'Desktops & Screen Saver' preference pane in the System Preferences in one of the two ways described below.
Control-click on the desktop (your actual desktop, not the file you just downloaded). Select "Change desktop background..." from the contextual menu that appears. Select the 'Desktop' tab in the preferences pane that appears.
Or, choose "System Preferences..." from the Apple Menu, and then click on the icon for "Desktops & Screen Savers". Select the 'Desktop' tab.
Next, click on the "Pictures Folder" item from the list. In the browse pane you should now see the desktop wallpaper you just put into your Pictures folder. Click on it and your desktop will immediately change to the new one! How do I change my wallpaper in Linux (KDE)?
Find a new wallpaper you like and click on the appropriate link to download the resolution you want (e.g. 1600x1200). A new window will popup will show up which gives you the option to either download the image, or view it in your browser. Choose the last option.
Right-click on the image and select "Save image as..." from the popup menu. Save the file to a convenient location on your hard disk. Next, minimize all your windows so that you can see your desktop workspace. Right-click on the desktop and select 'Configure Desktop...' from the popup menu.
In the System Settings module that appears, select the 'Background' icon from the left hand side of the window, then click on the 'Wallpaper' tab to your right. Finally, click on the 'Browse...' button and navigate to the wallpaper you just downloaded. When you are done, click the 'Apply' button in the to make you changes take effect.