This is a great plugin and I was loving it until just a few days ago the client reported not being able to create slideshows with more than one image.
What happens is when you go into the widget and upload/pick images to show in the slider, the first one registers fine, then as soon as you upload/pick a second image the image thumbnails show broken links.
I am not sure if there's any conflict with other plugins but I deactivated the only plugin that I added in the last few days (SEO by yoast) and it didn't help.
Here's the broken slideshow example:
The funny thing is, there's one instance of the slideshow that actually works.
I suspect the error happens when you are setting up the slider instance within the widget screen.
Any tips on how to troubleshoot this?