It could be useful to make the audio hotspot you've added invisible.
In the example below, I've added a recording of a cow saying "moo". I want the reader to tap or click on the picture of the cow to hear the audio hotspot.
Here's the process:
Add the audio hotspot
Add the image
Make sure the audio hotspot is layered in front of the image (right-click on the hotspot and choose Move to front)
Resize the hotspot as you need to, and whilst it's selected, click the Inspector (i)
Toggle on Invisible when reading
Now, when the book is in Read mode the reader won't see the audio hotspot at all, but the hotspot is still active when clicked on, and will play the recording.
