With all due respect, I'm not so sure that's correct, dflye (although to disagree more firmly I'd have to do some more experimentation!)
Some songs, even after powering the car back on (and the USB drive requiring a re-scan) still have artwork in them, whereas others don't. It would be strange to download some artwork and not others when I haven't even played anything since the car was powered up.
If what you say is correct though, that's really weird. I hope Tesla enables this in an update fairly soon. It's really stupid to continuously re-download album art instead of using metadata artwork when it wastes a lot of bandwidth and could use the wrong artwork.
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OK, I just checked on this.
The car is definitely NOT just downloading the artwork. Car's in the garage with no 3G coverage right now (I live in a rural area). I conducted a simple test by copying 3 songs to a blank jump drive--two of which were songs which I remembered to have been showing artwork, and one which didn't. Immediately when I put the jump drive in, the artwork was there on the 2 songs.
So it IS reading metadata.
The car did NOT see the stored picture from one MP4 AAC file (m4a).
The car DID see the artwork from another MP4 AAC file (m4a).
The metadata tagging software (kid3) indicated that both songs had artwork stored with them.
The car DID see the artwork from an MP3 file, and here's the crazy part: the metadata tagging software (kid3) did NOT recognize that there was any artwork stored in the metadata! Now I'm more confused than ever!
I'll get to the bottom of this, I hope. I need artwork for every song!
Step one: Get different tagging software...