I've been stalking your parallax walking guy David! Heads up - the links on your previous parallax weekly challenge entry and featured post on this site give a 404 error now - but I did I find your YouTube video which has been very helpful.
I was exploring this concept to possibly use for a client project - but I'm having issues with the background slider thumbnail image ending up very blurred.
I've tried a few tweaks, including resizing the image, and altering the story size in Storyline - nothing seems to improve the quality of the image.
I'm hoping that someone has an answer here...
Here's the demo showing what I've come up against - I haven't added any triggers yet, just the 2 sliders - I figure it's not worth my time finalising this unless I can sort out the blurred image issue.
https://360.articulate.com/review/content/277f346e-472f-455c-947a-fec3cbb548a3/review