Local artwork paths

Hello,

My plugin provides content for MyVideoNav (addDirectoryItem() stuff). I want to provide also thumbnails, icons etc for list items (the ones provided by default).

From what I can see, by default Kodi provides external urls for these elements http://host/some/path/file.jpg). Is it OK? Should’t they be local files? Does Kodi fetches all the graphics from the network all the time?

Or rather some mechanism uses these external paths for mapping to internal files located somewhere on a disk?