Images should explain themselves with clarity being added by the speaker or an additional word but principally achieved in composition. There should never be the need for a laser pointer, The Mac Spotlight or worse, the computer mouse. The supportive media that requires “explanation” is too complex.
The role of supportive media has been discussed elsewhere. It should add to the message but neither be script, handout or additional information. The slide should explain itself within 3 seconds and only remain projected for a limited period of time. It is not necessary to continue to display the same image for an extended period of time. Consider instead The Best Slide in the World.
Laser pointers, the Mac Spotlight and desktop mouse should never be used to “explain” an image; the image is too complex. Focus the attention of the audience by the composition of the image. Subtle use of animation including stepwise construction may help but an image that requires “explanation” will offer distraction from the message being delivered.
Images can contain text. One or two can completely change context and therefore meaning. A descriptive title to a chart can deliver understanding. These must be exceptionally limited. Multiple labels, sections of text or description means the image is too complex for simple understanding. An alternative or multiple images are preferred.
Images should explain themselves in presentations. Decrease the complexity of all images by composition, add single words to give context and spoken explanation. Never use laser pointers, Mac Spotlight or the keyboard mouse.