  This note aims at clarifying some mathematical aspects of what is known in
Physics as \emph{Picture Changing Operator} (PCO). In particular, we want to
show that PCOs are chain maps between the complex of differential forms (or
superforms) and the complex of integral forms on a given supermanifold. We
comment on the construction of (super)symmetric PCOs in terms of chain
homotopies and we provide some physically relevant examples of applications.
