The merchant from whom I bought this old African photo could not identify the woman but clearly the photograph had been taken a long time ago and was not preserved under the best conditions so the photograph is somewhat deteriorated. 

The overall dimensions are 19 3/4 x 15 3/4" (50 x 40 cm) The photo itself is 15 3/8 x 11 1/4" (39 x 29 cm)