У вашего броузера проблема в совместимости с HTML5
http://www.virtualdub.org/
If you want to add an animated gif to Windows Live Movie Maker, you'll have to convert it to a video file first. Virtual Dub is free, a safe download, portable (it doesn't install on your computer) and easy to use.
IMPORTANT NOTE: This tutorial was made using Windows Live Movie Maker 2011. The Burn DVD option that I use to save the project might not be available on Windows 8 computers. If you have a Windows 8 computer and are using Windows Movie Maker 2012, save the video as WMV files using the Save As drop down (where it says MPEG-4 at the bottom of the dialog).
Mac users:
http://www.youtube.com/watch?v=3mXgyFxJCDY
Like Movie Maker, iMovie only adds 1 set of images so you'll have to add multiple copies of the converted gif to the timeline in iMovie to make the gif move like it should.