This question just in from Gunnar Andreassen:

[I found this photo on the net some weeks ago (don't remember where). I can't remember having seen it before, but it must have been taken the same day as the photo on page 85 in Walt in Wonderland.

Based on the indentification of the guys in the other photo, they must be:

Bottom row: Walker Harman, Rollin Hamilton, Roy O. Disney, Hugh Harman,
Top row: Thurston Harper, Ub Iwerks, Rudy Ising

This photo must also have been taken by Walt Disney.

Can it have been published in a book ?]

[UPDATE: Just a little note re. the photo you posted today. My friend Are Myklebust pointed out to me that you had a photo taken the same day on your blog a couple of years ago: http://disneybooks.blogspot.com/2007/03/talk-about-great-entry-to-disney.html ]