In November last year, Gmail launched HD themes. These themes enable personalization of the background. For customizing the background of your e-mail, first, click the Gear icon located at the top right-hand corner of the screen window. Themes-> scroll down to Custom Themes-> light or dark. Move to the next page to upload pictures from My Photos that are already added to your Google+ account. You can even add pictures from your Android phone album or from a URL for additional pictures.
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