I don't mean the album art, but rather the image of the artist behind the album art.
AFAIK you can't have multiple layers of images in one mp3 file.
You would have to create one single layered picture with the man and the pasted Mr. Scruff "Ninja Tuna" over it. And then add this single layered picture as embedded cover art into your mp3.
It could be that this player software has some advanced functionally to do that by itself.
You can open such an mp3 in Mp3tag and have a look at the cover art picture in the lower left corner. What do you see?
I don't think it's a single layered image as the two seem separate from each other. For example, when you resize the window, they resize with it as two independent images. Also, the software I'm using is Windows Media Player, and I don't know how it managed to "stack" these two images. I imported this file from my old Windows 7 PC and while it didn't seem to show the artist's image in the old OS it does now. And it's not the only file that does this.
(This also works in Windows 10 as the software used is the same)
And here's another imported file with the same effect
So yeah, I suppose that the two images must be separate. I just wonder how they even managed to do it and if Mp3tag can do something similar.
As I wrote above:
Open such an mp3 in Mp3tag and check the cover art image in the lower left corner.
What do you see?
Do you see 1 image? Or multiple images?
Can you please show us a screenshot?
As I don't use "Windows Media Player" myself, you may follow this instructions to check how your WMP-library is searching for the artist covers automatically:
I think it's a feature of Windows Media Player that automatically downloads artist images.
I think I found the solution. Thank you for your time, and sorry for bothering!
Would you mind to share your solution with us?
It's indeed a feature exclusive to WMP, You simply open the program, go to library > artists and then you can see the image of every artist. I believe you cannot modify them though.
After that you can use Mp3tag to edit the artist of any audio file and it should automatically change the background!
I tried doing this with a random file and it worked.
You say that WMP is searching online for the background picture automatically with the current content in the ARTIST field of an mp3 file?
Example: If you have "The Beatles" as ARTIST content, you see a background picture of The Beatles in WMP? Or if you have "Mr. Scruff" as ARTIST content, you see the above men who sticks his index fingers in his ears in WMP as background picture?