Here is a good photo of a LGH officer (I know some of you can ID him, he is a prince or something). See my add for selling my entire photo collection. A. Meldahl
the Leib-Garde-Husaren-Regiment was split into two "Half-Regiments" from September 1914 to October 1915.
The I. Halb-Regiment was commanded by the regimental commander, Major Georg Freiherr v. Brandenstein and the
II. Halb-Regiment by Major Alexander v. Massow.
Although the beard here is not as well developed, I believe your man is the commander of II. Halb-Regiment, Alex v. Massow.