Beggars can not be choosers, Gul Hassan should have been glad they came with a coat of paint!!
General Yayha was the Chairman of the commitee which selected the site for Islamabad. The picture seems to have been taken during 1959 or 1960.
Field Marshal is a rank of the army. It has nothing to do with commanding two armies or anything like that. General Eisenhower was Supreme Allied Commander of all Allied forces, consisting of armies of 8 countries, but he was a simple 4 star General.
On the other hand the British Army had a number of Field Marshals. The Indian Army has had two Field Marshals.
The German Army under Nazi Germany had only one man who held the rank of Reichmarshal and his name was Herman Goering. No one in World War 1 or in the previous wars had held the position of Reichmarshal.