This is normally where one would consider using a Rollover Slidelet. Basically you roll over one area and a second area is revealed. The second area would then contain the image as well as the caption.
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Yes, normally, that is would I do...however, I always have trouble with rollover slidelet is that the audio and video attached to them play prematurely. For example, if the slidelet is on slide a slide midway thru the stack, it "plays" as soon as I start the module. So I've not been using this feature because I cannot seem to get it working the way I want it to...I've had this problem since version 3.