Violet, I felt inspired to further reply and explain the artwork in the Roman missal that you are talking about. It depicts Jesus crucified, not risen. The Blessed Mother is standing there to receive His Precious Blood flowing from His pierced side into a chalice. A priest offers sacrifice. Mary in the image is receiving, not offering. As to why you think the cloth on the rock is a shroud and that means He is resurrected is beyond me. He is nailed to the cross and bleeding. Perhaps the cloth is a shroud- the shroud that He will be wrapped in when He is placed in the tomb. 
The Blessed Mother is the Mother of the Church, the Body of Christ which we baptised are members of, so she is our Mother also. She is receiving His Precious Blood flowing from His side for us, for all the members of His Body, the Church. This is based on solid Catholic theology.