Repairing Leaky Corny Keg?

Hey all,
I was able to trace a large leak in my keg system today (that depleted an entire 5lb tank of Co2) to a leaky corny keg. It looks like its coming from the purge outlet, but im not 100%. Any help/ recommendations on how to fix this???

THanks

By purge outlet do you mean the pressure relief valve? #1 Always use a sudsy StarSan like solution on the lid of the keg when pressurized to see if it is bubbling (leaking) #2, take out the pressure relief valve and see if it is damaged, dirty, check the seat that it sits in to see if it is good. Insert the valve and tighten, try to repressurize, check for leaks, if it STILL leaks, replace the pressure relief valve.