Namu Butsu wrote:I suppose it could be nothing.

Yes, maybe it has no particular meaning in the sense that you're looking for, but I think that the Dalai Lama's image gives great blessings no matter where it is: in real-life, in a photo, on the internet, in a dream, etc. So I would just be happy that you could receive some blessings from another image of His Holiness. If the dream made you feel some extra inspiration or compassion, then try to use those feelings to benefit other beings.
Long live the Dalai Lama! Free Tibet!