hi nhamel,
The easy answer is that there are no pictures of Jesus. What are you going to put up? Some picture of someone else or some artist's rendering and say, "That's Jesus!" Similarly with Mary. Have you got an 8x10 glossy of Mary? If you do, post it for us please. All of the drawings in Bible study curriculums regarding the men and women of the Scriptures are nothing more than how the artist might have thought that they looked like. There are some who think that we may have a reasonable likeness of Paul, but I honestly doubt it.
So, the question then becomes, are you going to put up a picture that most probably looks nothing like the real Jesus or Mary in honor or memory of them? Some how I doubt that either of them, if we were able to ask them, would really feel honored that a picture of same strange person represents them.
Finally, Jesus said that we must worship in spirit and in truth. We don't need false pictures to worship in spirit and they most certainly wouldn't be the truth.
God bless you.
In Christ, Ted