My rule is that if art depicts a biblical scene, then it's just scripture presented in visual form. It's like a translation, then. It brings the story to life and helps people to become more intimately familiar with the word. I also consider a cross to be acceptable displayed at church or in the home or upon the believer as jewelry, for example. Empty cross only, and a reminder to believers that the cross is empty because Christ is alive, and to take up their own cross to follow him.