Got a prisoner neither bars nor chains can hold? Flatten them down to two dimensions, and stick them in a picture. From such a prison there can be no escaping, theoretically. As an added bonus, these pictures also make great Soul Jars. Life inside the picture can vary in many ways, starting with how much freedom the prisoner has. Generally, in the first two cases the prisoner does not age. With portal pictures they usually do, but in the third case both alternatives are reasonably common. The Harry Potter-style pictures, which are alive but aren't trapped people, are a borderline case.