Over the years we have been told that visual images are the most effective way to communicate in church. Admittedly, during my time at the seminary (1983-1987) this was not the message, although I'm sure that it was already being practiced, to one degree or another, at the parish level. With the advent of Powerpoint and big screens, the presence of visual images during worship and sermons has increased several fold. Personally, I have not been sold on this, but did not have any real research to support my views.
A recent article at the Steadfast Lutherans site offers that support. Two studies are referenced, one a D.Min project and the other an Ed.D dissertation. The first studied the effectiveness of projected images during the sermon, the other (included in the comments section) studied the effectiveness of children's sermons. I would highly recommend the article for your own review: "Why We Should Rethink the Use of 'Visual PowerPoints' in Sermon Messages."