When you added the album art using Picard, did you happen to notice how much the size of the music files changed? I ask because some metadata apps will automatically downsize images when they embed into the files to prevent creating huge files. If you embed a 2MB image file in a music track, the size of the music file should increase by 2MB. If it doesn’t, the app is probably reducing the image it embeds.
Like you, I used to prefer embedded art. But when I discovered what I just described, I decided it was better to have a single high-quality image in the folder than to embed huge copies of the same image in each music file. That eats up disk space in a hurry.
(I’ve been having issues with Plex not picking up my discrete images, so there’s a possibility that, if you change over to discrete images, you may still have a problem until that’s fixed.)
You may know this, but just in case: As long as Plex is configured to prefer local/embedded metadata, it will prioritize images in this order:
- Local discrete artwork files (folder.jpg, etc.)
- Embedded tags and images
- Online sources like Gracenote or Last.FM
