Oil Leak?

Who adjusted the valve? Did they use new gaskets after the adjustment? The old gaskets get hard and need to be replaced.

A great family mechanic. It runs alot smoother and a helluva lot better since having it done, yeah I had rubber gaskets on before and used cork this time. I think it may be leaking out of the rear of the valve cover. I'm going to check it again today.

Are there any problems that could result from this oil leak?