I got a little excited about this one - it's not every day a new image of Rupert crosses my desk! I'd say this one is probably from around 1914-15, when he was an up & coming actor in Hollywood, but not the moustached director he would become later.
He looks (to me) younger here than he did in, say, The Kaiser / The Beast Of Berlin in 1918 - though of course he was probably made up to look older for the film, it's hard to be sure.
In any case, this is a genuine Rupert Julian postcard, and I now own it! There's precious little information on it, just 'Pub. by Kraus Mfg. Co., N.Y.' on the reverse - but I doubt they were making postcards of young stage actors when he was there in 1912, I expect it's a Hollywood promotional photograph. Who knows!
(And apologies for not posting here on the blog more often - keep up to date with Rupert on his Facebook page, where I sometimes post articles about the silent era that don't directly concern him...)