If your running a Tumblr blog, you may consider to backup you data.
The Tumblr staff has released an app that do this for you. Just log in with you email and password, the app will connect to Tumblr server, gather all of your stuffs, pack it and store somewhere on your hard disk (well, it lets you choose where to save the file 😀 )
Unfortunately, there is only a mac version (lucky me to have a mac now 🙂 )
You can give it a try to this page: Tumblr Backup