Early this year, Microsoft and Pegasus Imaging crafted a plugin for Photoshop and let it out to the public. The plugin is for "HD Photo", which Microsoft has been lauding for a while now as a successor to JPEG. They tout the advantages it carries over the tried-and-true JPEG, such as better compression and better detailed information storage.
Their plugin has gone final now, Microsoft having felt comfortable to pull it out of the beta stage. During the beta it was renamed from Windows Media Photo to HD Photo, likely in an attempt to make it appear "friendlier". Morever, we all know how Microsoft just loves to try and shove a new standard upon the world (such as WMA). Even though they did make their licensing terms more agreeable to the world, they face an uphill battle in convincing people to switch from JPEG.
If you are using the plugin, you will need to update it before the end of the year as the beta plugins will expire then.