In Say it with Stick Figures Tim Riesterer outlines some research on the use of images in presentations:
In a recent set of experiments, Stanford University Graduate School of Business Professor Zakary Tormala tested the potential effects of whiteboard visuals against more traditional PowerPoint approaches. The aim of the research was to determine whether “whiteboarding” can enhance presentation effectiveness, as defined by metrics of engagement, enjoyment, credibility and — most critically — recall and persuasive impact.
The experiments used three different images – labelled ‘whiteboard condition’, ‘powerpoint condition’ and ‘zen condition’ below – to convey identical content. The whiteboard presentation had a statistically significant difference in engagement, credibility, presentation quality and recall. That is, it was better in each area.