Tableware, kitchenware, other household articles and toilet articles, of plastics: Other: Picture frames. . . . 

Simple and succinct, if the major composition of the profile material of the picture frame is plastic.

This also includes clear plastic articles like Bent Acrylics and Photo Cubes if they have a feature for holding a picture such as a slot or interleaving space.

      

Poster Frame                         Bent Acrylic                                                    Photo Cube          Flexible Pocket Frame