A good list of essential paintings for theologians can be found on the Faith and Theology blog. The list is by Kim Fabricius, contributor to the connexions blog, via whom I discovered this list. See also my selection of religious paintings in the National Gallery which has some overlap in terms of the artists at least.
It is interesting, though not surprising, to see Stanley Spencer’s Resurrection in the list. At some point I really must get around to writing a bit more about some of my other favourite Stanley Spencer paintings and where you can see them. ‘Resurrection’ is part of the Tate collection and the last time I was at Tate Britain it was on display, though they do change the selection they show quite regularly.