This post is a bit late, but for posterity, this cover commemorates Christmas in the UK in 2017.
Country: United Kingdom
Date of Issue: 7th November 2017 (first day cover)
The stamps on this cover feature both secular and Christian designs.
The secular designs on the left feature winning illustrations from a young artists competition. The snowmen were drawn by Arwen Wilson (9 years old), and Santa and his sleigh were drawn by Ted Lewis-Clark (10 years old). Well done Arwen and Ted!
The Christian designs feature works of art on the theme Mother and Child. The design on the two stamps in the middle of the top row are from Virgin and Child, attributed to Gerard David, c. 1520. The design on the two stamps in the middle of the bottom row are from The Madonna and Child, by William Dyce, 1845. The designs of the remaining four stamps are from Virgin Mary with Child by Quinten Massys, The Small Cowper Madonna by Raphael, The Sleep of the Infant Jesus by Giovanni Battista Sassoferato, and Saint Luke Painting the Virgin by Eduard Jakob von Steinle. But I am not sure which one is which.
More Information About the Issue
The insert to the cover provides more information about these stamps. Click the image below for easier reading.