Implicating sunlight -> light.

Reason: Light indicates that some source of lighting is prominent in the image. This would include sunlight.

Wait, do we really need tags for both dark and light? Doesn't the use of one tag imply that the other isn't applicable, and any posts that aren't tagged with dark can be assumed to be light (or vice versa)? Like how anything that's not tagged barefoot is assumed to have some kind of footwear, so we don't need a footwear tag. And then you have things like post #504755 which I would tag "dark", but is currently tagged "light". Certainly the light is the focal point of the image, but most of the picture is dark. So we might actually end up with posts tagged both "light" and "dark": light dark. And that's not even considering how people might try to tag a certain character as Light.

Well, dark refers to the overall composition of the image, light refers the light source being prominent. So, yes, post #504755 should actually have both. It sounds strange of course but it's actually a correct use of the tags, at least as they're now used.

Light is not, though, simply "any image that doesn't have an overall dark composition". I wouldn't tag, say... ::grabs an image off the front page at random:: post #512320 as dark, obviously, but neither would I tag it as light. Neither applies. So it's not an either/or. You can have both or none.