Do you mean summit of Bidean nan Bian, as this is the highest peak in Glencoe. It helps the viewer if you put the names of each peak. Afterall they all have names. But just looking at the photo it seems the Lairig Eilde, commonly known as Lost Valley is in the foreground, with the summit of Bein Fhada opposite. That would put the climber on the summit of Buachaille Etive Beag.