Image Size for Scrolling Panels in Storyline.

If you need images higher than 2048 pixels, you have to wrap the image in a svg

just tested a png (in svg) 500x8000 pixel in scrolling panel - no problem

I don't think there are image dimensions specific to scrolling panels, other than the overall Storyline max. image dimensions of 2048*2048. See here for details.

Thanks!