Welp, nevermind!
Lol, I found another way to achieve what I was looking to do.
Basically, I just wrapped my slideshow in a Group, then set the Group to Full Width, and set the interior (the Slideshow) to “None” (which is the max width of my images, since they are all uniform.) and set the interior content width to the max width of my images, and boom! exactly what I needed.
Thanks anyway though, great Slideshow Block! It does exactly what I need!
