6.1.2 Wood
4414.00.0000 
Wooden frames for paintings, photographs, mirrors or similar objects
Duty: 3.9%
Major structural frame composition must be wood or wood based material like MDF.
Paper such as laminated sheets, cardboard or chipboard have a different code.
Presenting or outer material  of the frame is important. If the base material is covered in textile that will be the basis for coding.
"Paintings" and "mirrors" as referenced above means that if a frame shell is imported it may be used to hold a painting or a mirror. The importation of a wood framed mirror is considered a mirror first (essential character), the frame is secondary and composition is irrelevant. Mirror codes start with 7009. Paintings and prints, framed or otherwise have a range of codes depending on materials, age and uniqueness (one of a kind "works of art").
Care should be taken not to code "Shadow Boxes" as picture frames unless they have an obvious slot or compartment for a photo or print. Wood Shadow Boxes, hinged with fabric or other mounting surface are coded as 4420.90.8000, which provides for wooden articles of furniture not falling within chapter 94 (floor standing furniture.) The rate of duty will be 3.2 percent ad valorem. 
graphic  graphic  graphic
Curvy Wood                             Casual Wood                      Wood Float