This is a Bimblebar. It is a pretty nifty widget, which allowes you to create scrolling image affects. You can make your own bar, upload your own photos and then paste the 2 lines of code in a post or in your website Head.
If you like the bar above, you can just reblog this post or just copy and paste the code below.
- Tumblr: http://bimblebarwidgets.tumblr.com
- Website: http://bimblebar.com/get-bar?bar_id=bb3