Elsewhere, my avatars are Helena Bonham Carter as Lucy Honeychurch from Room With a View, Frodo Baggins dressed up as Sherlock Holmes with a pipe and deerstalker (clipped off of Jeremy Brett’s head), and a picture of my cats.
Here, since I go by Miss Mapp, I would screencap a shot of Prunella Scales in that role, preferrably with a goofy expression on her face.