Gmail has always had a number of cool themes for you to choose from, but it has finally added the ability to create your own, letting you customise your inbox even further.
Creating a theme is easy: just go to Settings > Themes and under Custom, choose a light or dark theme. Then upload an image from Google+ or your hard drive to set it as the background for your inbox. If you don't have a photo in mind, you can also browse or search Google's featured photos to find one you like. We're not seeing the feature in our inboxes just yet, reflecting the usual Google gradual rollout process. If you don't see it, check back later. In the meantime, see the video above for a demonstration of the new feature.
Custom Themes in Gmail [Official Gmail Blog]