Those are not triple 7 engines:
United Technologies Corp.'s Pratt and Whitney Aircraft Group in East Hartford, CT received a $14.5 million contract modification to provide for FY 2005 Final
Economic Price Adjustment (EPA) for 27
F117-PW-100 engines. The F117-PW-100 powers the C-17 Globemaster transport aircraft, and is the military version of the
PW2000 engine that powers the Boeing 757 and Ilyushin IL-96. This work will be complete December 2005. The Aeronautical Systems Center at Wright-Patterson Air Force base, OH issued the contract
A triple seven engine is a LOT bigger than that.
the photo shows a c-17 performing a short field landing(look at the position of the slat/flap) using reverse thrust.