Your images are almost covered by the shadow of the slider above it.
It’s a transparent div, so you cannot see it, but you will detect it using firebug.
Please use the following codes in your Theme Options -> Custom CSS
It will bring your images to the top of the “stack”, so that you can click on it.
The above class names, for example wp-image-5467 is actually the id of that image, if you change to another image, we will need to rewrite this css code.
Please clear your mobile and desktop browser cache before re-visiting your webpage.