Rather than present students with an image on the screen and immediately start discussing what they can see and what it might mean, provide them instead with a completely blank screen. Then tell the class that you are about to show them an image for exactly one second before discussing what they can remember about it.
Proceed to show the image for just one second and then turn the screen off again. Students then have to discuss with a partner, then in small groups, what details stick in their memory, and what the overall relevance and meaning of the image might be. There might be particular questions about the source that might be asked at this stage by the teacher (‘did the image create a negative or positive impression about…?’, ‘when/where/by whom/for whom do you think this image was produced?’ and so on).
Finally, bring the image back onto the screen to determine how accurate their memories and interpretations happen to be, and to focus on any remaining details which were overlooked. At this stage students can answer a set question about the source, or be provided with further information about it to help them make sense of it fully.
This would work well for political cartoons, historical photographs, works of art, artefacts, or even statistics which are presented in a visual way. The central point is that rather than look at these images from the outset at leisure, a sense of anticipation is built up and students study them briefly but with intense focus from the outset.
Taking it further
Before showing the image, the class could be arranged in groups, with different people given a different thing to think about as they look at it. A simple structure is to frame focus points around question words (Who is shown?, When was it produced?, Why was it produced?, Where was it produced?, What is its essential message?). After the image has been shown, each student could then feed back to the rest of the group with their thoughts so that between them they come up with a thorough interpretation.
Students could be challenged to sketch the picture directly after seeing it, rather than simply discuss it. These sketches could be compared with other members in the same group to produce a team version, with credit given to the team which includes the most detail and provides the best interpretation.