If you click on the painting above by Lucas Cranach, you'll see the altar he made at Luther's church in Wittenburg. It represents a time period in which protestants understood and used iconography. This makes me want to hunt for protestant icons now.
This picture portrays the last supper. What's interesting is that all the disciples are in a circle. And Judas is being fed first! Talk about grace. At the bottom you get a picture of Luther preaching and of course pointing to Christ.
This Sunday we took the church kids to the Interfaith Week art show, which indicated the way that children ranging from the LDS to Judaism to the Disciples of Christ conceive of their faith. Those pictures tell a story of self identity as potent as most icons.
If one wants to see how protestant churches are seen by someone who is on the outside (doesn't it seem perverse to speak of insiders and outsiders when it comes to such a thing?) check out Oliver's posts as he visits various churches in Mississippi.
His most recent was to a presbyterian church in Oxford, which is one of the only moderate to liberal congregations I could find in Mississippi. If there are other congregations for Oliver to visit that others can recommend, feel free to post here or on his site.