What's interesting about this photo is that MG Scott is wearing the M1902 full-dress uniform for mounted officers, M1902 officer's saber, and the M1912 hat (with the wider crown), but he is wearing the M1872 version of a general officer's sword belt -- with the long strap from the center of the back of the belt and a short strap on the left side.
Along with the M1902 uniform & saber was the M1902 sword belt -- which had a long & a short strap (fastened side by side) -- worn on the left hip.
As a general officer, Scott was able to design his own uniform. First time I've seen the M1872 belt worn with a M1902 uniform.
Also, this is a great closeup of the full-dress sword knot for general officers -- which is distinctly different from the sword knot for all other officers.
Seems he has the field version of the saddle cloth, rather than the dress version -- even though he is wearing his full-dress uniform. The stars and the General Staff chevrac appear to be in a subdued finish, rather than bright silver for the stars and colored enamel for the GS insignia (as shown in the example at the top of this post).
I would guess that this photo was taken on Ft Myer, VA, near Quarters #1 (General Leonard Wood was the first Army Chief of Staff to live there, beginning in 1910. Every Army Chief of Staff since then has lived there.) MG Scott lived there from 1914-1917.
Interestingly, MG Scott personally negotiated the end of the Bluff War in Utah (March 1915), one of the last fights with native Americans involving the US Army.