Its leaking between the body of the injector and the tip.  Fuel runs up to the top of the  head, looks like a line or bottom seal leaking.  Sometime tighening the hold down scews will stop it, the right way is to take the injector out, take it apart and lap the sealing surfaces on a lapping block. Ive lapped them on a peice of glass before, that seems to work.  Its possible the nut didnt get tightened enough when it was assembled too, if the injector has been in a long time, thats usually not the case.   HTH