This antique lamp has two paintings, a pair of couple wearing dresses from 17th Century. From this paintings, the age of the lamp can be measured. The painting inside the Frame of the lamp is " The Blue Boy and Pinky" of Thomas Gainsboroug
The Blue Boy
"The Blue Boy" is very similiar with the painting inside the lamp.
"Pinky"
This antique lamp is similiar with a lamp from Barr Antiques, UK (below).
It is said that it is Edwardian, but from the comparisson between two lamps, it is known that a opaque shade and clear green glass reservoir have been missing. From the decoration, we can see that the first lamp is more gracious.