Question About Sunrise and Sunset Tags

This may be a stupid thing to ask given that there are only 242 entries for the two, so if it's not too much trouble, could somebody please inform me if I'm just taking up space by asking this?

So my question is:
How can one tell a rising sun from a setting sun in a static picture?

Could there a be good tag for both?
I tried submitting the implication:"twilight" but it was rejected for being too common...
what does that mean?

Once again, sorry for being a bother to you all...

I think this is similar to dressing/undressing. I think, from a picture, it's hard to figure out which way the event is going, and I'm not sure if the difference is all that important to most users. That's why I think aliasing sunset to sunrise or vice versa would be a better idea. But maybe there are sunset/sunrise aficionados out there who strongly disagree.

I agree with just picking one or the other. Even if there are a few cases where you can tell (more likely with dressing/undressing than sunset/sunrise), they're not enough to justify keeping separate tags, I say.

Even if there are sunset/sunrise afficionados, does the average artist really care enough to distinguish the two events visually? I say alias it.

As for the undressing thing, there are situations where you can tell someone is getting dressed, but the default should probably be "undressing" if it's not clearly "dressing". This one's a bit more iffy though to me.