You can edit your picture or profile information in the Profile tab under your account settings. You can also click on the Edit profile button that appears on your profile whenever you are logged in to that account.
To change the location, website, picture, or bio listed on your profile, follow these steps:
If you would like to change your profile's background image or theme, please read How to Customize Your Twitter Design.
Click here to troubleshoot problems with profile photo uploads. If you cannot update your settings, visit this page.