Transparent pngs stacking on top of each other

I’m using this plugin with transparent PNGs with the “fade” setting. It looks like the next image fading in shows up behind the current image, before the current image fades aways. So, while the images are transitioning, two images are visible at once. Is there a way to disable this?

https://www.ads-software.com/extend/plugins/jj-nextgen-jquery-slider/