Twitter tips--Selecting a custom background image in Twitter
If you want to ramp up the “wow” factor, if you want to use your Twitter profile as part of a personal
or business branding strategy, or if you just want a Twitter home that truly reflects your style and
personality, then you need to augment your design with a custom background image.
You might think this is just a simple matter of uploading your favorite photo, but Twitter offers several unique challenges when it comes to selecting a background image. Before I get to those, run through the steps you need to follow to apply a custom background image to your Twitter profile:
1. Sign in to your Twitter account.
2. Click Settings. The Settings page appears.
3. Click the Design tab.
4. Click Change background image.
5. Click Browse. If you’re using Safari, click Choose File, instead. A file selection dialog box appears.
6. Choose the file you want to use, and then click Open (or Choose in Safari). You can use either a JPEG or a PNG file, and the maximum size is 800KB.
7. If you want Twitter to tile the image to cover the background, select the Tile background check box.
8. Click Save Changes. Twitter updates your profile with the new background image.
Reference : wiley.com