Emby Missing Local Metadata Actor Images (Not a Network Issue)#
When setting Emby to only read local metadata, we may encounter the issue of missing actor images. Most solutions found online involve modifying the host, but we know that the network is not the problem and the nfo files are complete. So why are there no actor images? Moreover, a perfect poster wall with bare actor tables really affects the viewing experience. This is because Emby has its own way of reading actor information and does not follow the nfo path. Therefore, to solve this problem, we need to select the scraping options.
After Emby has finished scanning the media library and the poster wall has appeared, in addition to setting "Enable Real-time Monitoring" and "Read Nfo" as mentioned in the article Emby Settings: Only Read Local Metadata Without Scraping, we also need to select "TheMovieDB" as the scraping option, as shown in the following image. 
The same applies to movies. 
Then click on "More" in the media library, select "Refresh Metadata," and choose "Search for Missing Metadata" to refresh.
Wait for the refresh to complete, and you will see that the actor images are now displayed in full. 
As a side note, why do we need to select the scraping options after the library scan is complete? This is to save computational resources and allow Emby to first read the local Nfo files, and then use scraping to fill in the missing ones.