Every post should include a visual whether it be a photograph, a map, a video clip, or drawing. Visuals provide context, lure readers in, and communicate ideas. CoLab Radio welcomes image-centric posts with little text.
Look at Radio in Pictures: http://colabradio.mit.edu/?page_id=3980
These images and their captions summarize the entire post, and probably helped attract readers to the post in the first place. Powerful images can tell the whole story without words. Always remember to credit the source of the visual material.