The gospels give no details about how Jesus was removed from the cross, only that Joseph of Arimethea gained permission to take the body down for burial. For most of Christian history the subject has not been treated in any set pattern, but in the 12th through the 14th centuries many images of the Descent follow the pattern in the mosaic pictured at right: A bearded man on the ground uses tongs to remove the nails from Jesus' feet while another on a ladder lowers the body down to Mary. The two men are presumably Nicodemus and Joseph of Arimathea, who remove the body in John 19:40.
In Duccio's painting of 1308 (second picture on the right) and in some others in the 14th century and later, the man below is not removing the nails but untying the feet. In the mosaic, Mary kisses her son's arm, but in the Duccio and many later versions she presses her face to his and the arm is kissed by Mary Magdalene.
This pattern continues for a while after the 14th century, but there always were many individual approaches to the subject and starting in the 15th there is little consistency of approach.
A image of this type is traditionally referred to as "The Deposition." However, a number of images with that title are actually about the placing of the body in the tomb (example).
Prepared in 2016 by Richard Stracke, Emeritus Professor of English, Augusta University