Dodge City Peace Commission, early June, 1883. The men went to Dodge armed to support Luke Short in a confrontation with business interests that wanted to force him out of town. The title of "peace commission" (later applied to the photo) was ironic. Their presence did produce a peaceful resolution. According to a biography of Wyatt Earp by Casey Tefertiller, the photo was taken in the Conkling Studio at Dodge City in June 1883 and first appeared in the <i>National Police Gazette</i> on 21 July, 1883. 
<p>From left to right, standing: W.H. Harris, Luke Short, Bat Masterson, W.F. Petillon. Seated: Charlie Bassett, Wyatt Earp, Frank McLain (possibly "M. C. Clark"; see <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110207143248/http://dodgecitypeacecommission.com">Dodge City Peace Commission</a>), and Neal Brown
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It's a "published pre-1923" historical photo, so the release should read that. <a href="https://en.wikipedia.org/wiki/User:Sbharris" class="extiw" title="en:User:Sbharris">Sbharris</a> 21:36, 3 March 2006 (UTC)
Conkling Studio
<a rel="nofollow" class="external text" href="https://web.archive.org/web/20110207143248/http://dodgecitypeacecommission.com">Dodge City Peace Commission</a>