How to See Someone's Twitter Background
Twitter allows users to customize the looks of their profile pages with background images that express their personalities. However, because of the layout on a Twitter profile page, it may be difficult to see much of the background image, leaving you wondering what the picture really looks like. Sometimes users even create a custom image with contact information, which may be obscured or cut off by the timeline. Fortunately, you can view the background image by itself with just a few clicks of your mouse.
Navigate to the Twitter profile page of the user whose background image you want to view.
Right-click with your mouse on any visible part of the background image.
Click "View background image" from the menu that appears. This will cause the image to open in a new window or tab, depending on your browser's settings, as it looks without the Twitter timeline or profile information on top of it.