I have SkyDrive photos on my desktop and a laptop and they are included in Photo Gallery.  They are  synchronized with my SkyDrive online.

When I tag a picture on my laptop in Photo Gallery, the photo online and on my desktop become tagged.

When I tag a picture on my desktop in Photo Gallery, the photo online and on my laptop become tagged.

When I tag a picture online, the photos on my desktop and laptop do not get tagged in Photo Gallery.

Why?