slider not sliding in multiple themes

I have downloaded multiple themes with a featured post slider function\ it works fine till upload my images, (or create posts in a category)
the problem is that once i set this up the slider no longer works on the homepage.

so it works with thier images in the preview, but not once I set up post and a featured category, the themes are all similar and it happens with every single one of them, making me suspect it si a compatibility issue

any suggestions?
here is the site:

https://lewmarartistmanagement.net/

thanks alot