This picture is a capital letter “S” that is entwined in vines, with stylized vine leaves.
The image is black on a white background. It is made by scanning the printed initial in a book. The initial would probably have been made from a wood engraving.
The S itself is solid black with an outline or double border all round it, and has semicircular notches in the top and bottom ends of the S stroke.
The vines go "in front of" the initial in places, that is, between the initial and the viewer, and have shadows (made by lots of finely-spaced parallel black lines, as is usual in engravings).