I was wondering which yaoi this picture is from or if it's just fan art.

http://www.mangago.com/read-manga/mitsugetsukei_honey/mf/v01/c000/35/

Please and thanks ^^

It's taken from an artbook by popular manga-ka Ayano Yamane (View Finder, Crimson Spell). The art book is called Ayano Yamane Illustrations Aya. There are scans of that art book floating around too...I'm not sure if the picture itself is from a particular manga as these art books tend to be collections of a variety of art from old works, one-shots, and illustrations for light novels too.