6-3-5 disables slider stacks?

I’ve used a number of slide stacks with my web site, including Yuzool Themes Slide, Stack Maniac Refined Slider, and Joe Workman Scroll. These work fine in my preview, but once uploaded, the images disappear. Also, if they do show up (thumbnail navigation), the slider won’t move past the 2nd image and freezes. Anyone else experiencing this?

Almost always if things look one way in Preview mode and look different after they’ve been published then something went wrong during the FTP (or however you publish the site). There are a dozen reasons why this might have happened – but putting those aside there is one good solution.

This is so common that I put a permanent answer here: