Ladies, I think we need to start tossing around new thread name ideas already! I know it's early but let me put it this way - this new thread has only been open for 8 days and we're already on page 6!!!
I'll take a punt on what episode this picture is from. He's wearing the season 1 tie (he did occasionally wear others in season 1, but that was the standard) and that's McGee's Norfolk office in the background. Sub Rosa is my first guess with a slight chance of Eye Spy.
Modified to say I when I "quoted" the photo to post, the image name had "eyespy" in it. Sort of gives it away.