The fade effect is available on the columns only. You need to turn the toggle on, please see image attached.
This 3 images you are referring to actually is just 1 image.
It is one background image on the section and each column has a color background with transparency which gives this effect of 3 images, but if you look carefully you will notice it is just 1 image.
You can switch the background image of your section.
Or you can add to the style box of each column the following CSS to use a background image on each column individually instead of a background color.
More information about backgound image css on :
Hope it helps!