Thanks for the response but "replacing the color with the exact same one" flattens and thus eliminates the shadowing effect I'm looking to achieve. After some more testing today, I'm convinced Storyline360 has some issues with Outer & Inner Shadow Presets.
The Presets in Slide View produce a much more pronounced Shadow than what is seen during Preview Mode and beyond. And if the Preset is manually adjusted, starting with changing the color from black (#000000) to another, there's high potential to wash out and flatten the entire effect. Almost as if the image was simply Recolored instead of a shadowing effect being applied.
To remedy this, I'm going in a completely different direction:
1. *Make sure your original image is still saved somewhere so you can get back to it if needed.*
2. Apply shadowing effects to image on slide.
2. Right-click on the slide image and Save it as is. Don't export the original because the effects will not be exported as part of the image.
3. Re-insert saved shadowed image onto the slide.
That's my workaround until this all could be improved, and to me this anomaly would be something worth exploring on Articulate's end. Thanks!