design - i want a widget that shows a BIG image over the whole size of the sidebar

hey all. this is a design question.

i'd like to know if there is a widget that can put a large image in the sidebar instead of a bunch of other things. especially one that would take up the entire size of the sidebar and be responsive. For an artistic site. Like, a big picture of a figure standing or whatever, even a slider that's shaped vertically nice that transitions smoothly while the reader is reading posts in the central area of the page