I am aiming to produce a Kindle title from an original print book file created in InDesign with lots of diagrams. One request the author has is that when an image is double tapped so that it enlarges on the Kindle reader’s screen, the caption for the diagram should also be readable. He also wants the caption text in the ebook to be searchable.
I propose to solve this problem by creating a separate image with caption for each diagram. This means I can leave the caption text searchable in the run-of-text, but if the reader double taps on an image, then an alternative version of the image appears with a rasterised version of the caption underneath it.
If this sounds really dumb to anyone, because you know of a better way of proceeding, please feel free to speak up. But my main question is: How do I structure the ebook code so that the ebook displays the ordinary image with caption below it in the run of text, but displays the alternative image with rasterised caption beneath when a reader double taps on the image.