I find it harder to engage in System 2 when there are images around. Heck, even math glyphs usually trip me up. That's not to say graphics can't do more good than harm (for example, charts and diagrams can help cross inferential distance quickly, and may serve as useful intuition pumps) but I imagine that more images would mean more reliance on intuition and less on logic, hence less capacity for taking things to analytical extremes. So it could be harmful (given the nature of the site) to introduce more images.