I haven't done one of these for ages (perhaps for good reason) but then this one just popped into my head so I thought I'd share it. I've been thinking about universal rules and how certain principles can work for all sorts of graphic design stuff and I think this is one of them.
(Yes, there's probably exceptions, but then there usually are with rules.)
I've heard and read this expressly applied to advertising but I think it can work for almost anything, like the student magazine I'm working on (hence simple headline with photo of hamster). It's a basic principle, at times ignored: creative heading with creative image - idea overload; "straight" heading with "straight" image - idea underload*.
So: Really interesting image goes with simple words; Oh so clever copy line with straight forward picture; Si Scott typography over...er...nothing probably; that kind of thing. But you probably knew all that.
* Not sure if that's a word.