Moon+Reader: Linking to external resources

I have a number of ebooks that contain (small) images that are links to bigger images. The small image is embedded in the epub, the bigger image is external. Code looks like this:

The problem is that I can't seem to activate the link to the external image. It works in other ebook readers, but in Moon+Reader a tap on the image just activates the next/previous page or options action, depending on the location of the image on the page.

Ordinary links, to other parts of the epub, do work as expected.

I assume I missed a critical setting, but which one?

I'm running Moon+Reader Pro 6.5 on Samsung Galaxy Note S4, Android 10.