How to put animated icons on your tumblr info?

You can use Video Avatar. It's easy and may help you!)
  Answered Feb, 08 2011

From the Dashboard menu (the one with Text, Photo, Quote, etc. icon options) click on 'Photo'
Click the 'Choose File' button
In the File Selector Dialog box that pops up find your .gif file that you want to upload and click the 'Choose' button
To add more images click on '+ Add another photo' button and repeat from step 2 above
Write your post text in the Text Input box below
Click Preview or Publish to finish your post Answered Dec, 31 2010

Just make sure that it's a .gif pictureif it's saved as a .jpeg file, it won't move.
If you want to get more information about this tool you can visit:
http://answers.yahoo.com/question/index?qid=20101214134607AAeMTyK Answered Mar, 02 2011