Update the background picture on your Tumblr blog, and the change might spark new creative ideas that catapult your blog in exciting new directions. Different Tumblr theme creators use alterna.

How to Edit a Tumblr Background. You can edit a few attributes of the default theme in Tumblr through the Web interface, ... For more flexibility, you can apply a custom theme to your Tumblr blog.

Tumblr is bringing in-depth blog theme customization to its mobile apps. On iOS and Android, you can now tap on a user’s name and see a mobile-optimized design for their page.