How do you tell your viewers how to zoom out of a "zoom picture"

I took some screenshots of some documents that I am using as images in a module.  I used the "zoom picture" feature in the picture tools area of Storyline.

When my client reviewed the module, he wanted to know how viewers would know to zoom back out.  Now, my off the cuff response would be something along the lines of "well isn't it obvious that you just click the picture again?"

I wish there was a red circle x similar to the lightbox slides (I will be putting this in as a suggestion), but how would you go about telling viewers to go back out of a zoomed picture feature?

My ideas so far:

• Don't use the feature and instead make a hyperlink to the actual document.  I rather keep viewers inside the module though.
• Use the zoom feature but fake it out with a zoom layer.  But honestly, what's the point of this feature at that point.

Any suggestions or ideas you all have would be great.