You may prefer to have more personal look and feel for your Twitter Account , you can do so as Twitter give an option to customize profile. Twitter allow users to use custom images and backgrounds.They are some basic template that twitter presents to it users.
Here is step by step guide on how to change twitter background and design
Step 1:Login to your twitter account and click Setting at the top of twitter page.
Step 2 : Click the furthest tab on the right, labeled Design.
Step 3 : Select a template by clicking on it,and save changes or upload your own image by clicking “Change background image.
Step 4 : Click on Change background image and browse for your own background new images and click on Upload
Step 5 : Wait untill it uploads completely and click on Save Changes.
Step 6 : You also you can change design colors if you want,click “Change design colors” Click any of the boxes to change your colors; click Save Changes when you’re finished.”Now You should see your new background.