suspend fun downloadThumbnail(wallpaper: Wallpaper): Wallpaper.ImageFileState = withContext(dispatcher) { downloadAsset(wallpaper, Wallpaper.ImageType.Thumbnail)
Downloads a thumbnail for a wallpaper from the network. This is expected to be found remotely at: <WALLPAPER_URL>/<collection name>/<wallpaper name>/thumbnail.png and stored locally at: wallpapers/<wallpaper name>/thumbnail.png