Morod,
This is fine for one photo, but what if I want to put a new Album of 21 photos into my Mobile Me Gallery?
Tom G.
Find the album you want to add to the MobileMe gallery. Click on it, then in the lower right of iPhoto, click on the Mobile Me icon. A box will ask if you want to publish the album. Click on the Publish button and it's done.
Now if you want to add 21 photos to an already published album, drag the 21 photos from wherever they are in iPhoto to the album you want to add them to (if the 21 photos make up their own album, simply merge the two albums). Drag the album with the new photos to the existing same-named album under MobileMe Gallery in the left hand bar. All new photos will be added to the existing gallery. You're done.
Let me know if you meant something else.