Dear @samdismore
It is possible but you may wish to seek the aid of a developer for this one,
Some Javascript would need to look at the contents/data of the image, register whether it is black or white and then change the Navigation accordingly - bit tricky but would be possible.
Another way which is probably easier is to manually set a class/ID for the slides that have the black background:
Screen Shot 2020-12-19 at 12.18.21 PM.png
Set the the ID to e.g #special
And then when the slide with #special is active in the slide the navigation changes accordingly. This is the one i would go for.
There are more ways for sure and hopefully people will share their thoughts!
I hope i have been somewhat helpful Sam, apologies that i cannot create a tutorial just now!
Let me know your thoughts and have a wonderful day :)
Sincerely
Richard