Preview images

When browsing an external USB drive attached to an LG TV running webOS, preview thumbnail pictures are shown for files and folders. For folders, they’re generated from the “first” four files. For files, they either show an embedded cover art (although it’s unclear to me which metadata tagging standards are supported) or a preview generated automatically for images and video files.

Other operating systems and file explorers support manual override for files thumbnails, e.g. in Windows a file named folder.jpg or folder.png is used and is expected to have a square aspect ratio. Media Center software like Kodi support a number of such specially named files for various aspect ratios and roles (e.g. portrait-oriented poster, disc cover, semi-transparent logo, character art, landscape background artwork, episode and season banners). Therefore, one or more of those image files may be present in a directory.

I found no user guide how to influence the generation of thumbs for neither files nor folders. I did find references to mediaindexer. com.webos.service.mediaindexer | webOS Open Source Edition However, that’s hardly helpful in the end.

  • Is there any way to override the automatically (and often slowly) generated folder thumbnails?
  • Where could I post a feature request to propose this be added in a future version?
  • Is there any documentation of support for ID3 tags, Vorbis comments, MP4 and MKV metadata, especially regarding embedded pictures? (other than reading the source code)


  1. If needed, you might be developed app or serive using mediaindexer. You can scan media files from the specific path, and get the file URL, and then load media using the media tag of HTML.
  2. Is your a requested feature for the TV platform or the OSE platform? You should request that feature to the TV developer site if it is for the TV platform.
  3. For the web app, I think node.js is one of the solutions, node.js (using external npm modules) provides various parsers for processing you mentioned things. so you can create a javascript service to solve your question.