I have created a slider webpart to be used by end users for their SharePoint publishing sites. Its working fine. Only issue is whenever end user need it for a different website with different content, they have to modify HTML. Any idea to create something where user can just input their text and images and webpart picks it up so user don't have to edit HTML. Any help/suggestions are highly appreciated.
One good way to create a slideshow web part is using Content Search WebPart. You only have to write html code for the UI layer by creating display templates and it gives you enough flexibility to configure the datasource using search query. See this example of Image slider using CSWP.
You can have a configuration list from which you can read the data and build the slider. The list can have some basic columns like -
- Image URL
Your slider code can read this list to get the necessary data and render the slider. If you want to have the slider in a different site all you have to do is create the same list in that site.