Deleted Album Art reappears on car's USB audio player

My process for ripping CD's for archive purposes & eventual use on USB thumb drives in my car & on my home audio is as follows:

  1. Rip Cd to Flac

  2. Perform a global search in the Music folder using Windows file explorer in order to locate & move .jpg cover art files to a separate, independent dedicated folder on my CPU hard drive (just in case i ever want to reinstate the 'folder.jpg' files down the road).

  3. Modify idtags and, i assume, the metadata for each Flac file as necessary using MP3Tag. This includes the removal of any cover art within the flac files (art appears in MP3Tag as a number under the 'cover' idtag column (ie. 1, 2 etc...)). The cover art image also appears in the cover art pane in the tag panel from where it is then removed.

  4. Once items 1 thru 3 have been completed, i convert the Flac files to MP3-320 kbps.

  5. Copy the Music folders w/ MP3's to USB thumb drive using Windows (10) file explorer.

Comment:
When i use the USB in my car, the album art is magically present despite it's earlier jpg relocation & supposed metadata deletion. There is no album art presence when the Flac & MP3 files are viewed in Windows file explorer, groove music or WMP.

Questions:

  1. Does the embedded album art that I removed from the Flac file metadata get reinstated in the MP3's during the conversion process ? If yes, this wouldn't explain their absence within Windows (including when the USB thumb drive is viewed).

  2. If no to Q#1, could the presence of the desktop.ini file on the USB play a role in the reappearance of the album art in my car ?

  3. If no to Q#2, does the simple act of copying the MP3's somehow reinstate the album art metadata ?

It's not the end of the world that the images appear on my car display, but i'm curious to understand how something i've supposedly deleted has reappeared.

Thanks in advance for your responses. I look forward to your insights.

If you can confirm using mp3tag on the files on the USB key that they do not have album art in the metadata, then they are not the source.

Many car radios have the Gracenote music library built in. And this provides the artwork and more from files that it can match.

Here you have another program for the transformation - does that program add covers again?
Have you checked the files on the USB thumb drive with MP3tag whether they have embedded covers?
Have you checked the thumb drive for hidden files like folder.jpg, albumartsmall.jpg and thumbs.db?
And as @MotleyG said: there are car stereos that have their own internet connection and download pictures when they recognize a track.

Or to answer your questions:
1: no
2: probalby not desktop.ini but other hidden files
3: no.

MotleyG & orenkhino,
I checked the files on the USB thumb drive using MP3Tag. No cover images are present.
I also checked online to see whether my car's audio system uses Gracenote. It does.
Seems like you have determined the cause of the album cover reappearance in my car's audio display.
Once again, you have both assisted & informed me. Thanks.
FYI: orenkhino,
The name of the conversion program I used starts with a 'db' & is of German origin. I did consider that it's conversion tool may have played a role, but didn't want to introduce other software into a discussion on this forum. I figured I could always ask on their forum should it seem the likely culprit (which it was not).