Beauty of light in darkness
http://dark.pozadia.org/images/wallp...36-240944.jpeg
http://ih1.redbubble.net/work.425240...ing-sunset.jpg
There is something beautiful (to me, at least) about a mostly dark image with some light in it. I suspect the allure is more than the fact that it's eye-catching. It seems like the mind subconsciously considers it a metaphor. For what, I'm not completely sure. The darkness represents some negative state - loss of hope, abandonment, depression... And the light represents freedom from that negative state, some 'beacon of hope', like love or the realization that the negative state may be escaped.
I find this true with other forms of art as well: poetry that seems 'dark' and ugly on the surface but contains beauty if you look harder, certain music that is dark and sad but beautiful at the same time.