Biographical information on Zorn can be found here and here.
As mentioned, Zorn was a leading portrait painter. He is also known for his etchings and the many paintings of nicely padded young, nude Swedish women in the outdoors. As I recall, one of the essays in the Gardner exhibit catalog mentioned that Zorn didn't seem interested in painting still lifes. And a quick scroll through Zorn images on Google suggests that he didn't paint many pure landscapes either; his outdoor scenes normally included people -- especially those nudes. But he did manage to paint some genre scenes. Here are a few:
Could this be of one of those notorious "pea soupers" that used to plague the city?
Yes, the place still looks something like that as best I remember. But instead of those women, what I mostly noticed were tourists embarking and debarking Spanish ferries.
A highly unusually setting for Zorn.
Passengers crammed into a Paris horse-drawn omnibus must have fascinated Zorn because from this setting he made at least several studies, two paintings and one etching (of the final painting). I think his depiction of the beam of light on the cheek and coat of the women in the foreground is a brilliant concept well-executed.
This painting was controversial in its time because the subject was (or was thought to have been) a drunken prostitute.
Perhaps Zorn's most iconic genre work.