Count the number of images using import.io

I tried using XPath count()

to get the number of images on the slider. For example:

count(//*[@id="slider"]/div/ul/li/img)

      

        
        
        
      

    

It works when I use the XPath tester (XPath Helper extension for Chrome), but not when I use import.io, which makes me think it doesn't support count()

. Is there any other way to get the count of the number of images?