Regarding the "Manage Covers" window in Mp3tag: Could support be added for setting the display priority of selected images?
Use case: For multi-disc albums, a user might want to set either the individual disc cover or the box-set artwork as the default image to display first.
I think that the display relies mainly on the player's features.
In MP3tag you can modify the order of the embedded pictures. If this is taken up by the player is beyond the controle of MP3tag.
The next question would be: does the player show more than one embedded picture?
Trial and error? Or a look at the documentation of the various members of the tool chain and which features and functions they have?
There is no way to define a "priority" for embedded pictures.
One player may take the first picture, the next may take the last one, a third may take the one with the property "Cover".
If you want to be sure that one particular picture is displayed, then embed only a single picture.
Actually, there is a way: upon adding a new cover to an existing one, which is sitting at position, it goes to number 2 (and you have to click back and forth between the two pictures for choice). If you want to get number 2 in at number one (swap them), you first remove number 1. Then— if—you wish to retain the original number 1, you just add the cover back at number 2. It takes too much back-and-forth, though. Its especially needed when box-set covers and the covers of its nested discs are to be displayed: the box-set cover for all tracks at number 1, and the individual disc covers going in at number 2 — or the other way around.
It is not necessary to remove already embedded pictures.
SImply open "Manage Covers..." and drag the picture to the desired position and save the changes.
The order in the MP3tag display still does not determine any priority. If your player happens to take the first picture then that is the feature of the player and you found a way to see the favoured picture.
It is only unavailable if the covers vary.
In your multi-disc-scenario you would have to select each album separately to set the common picture and the individual one.
Just a reminder: this function should also work if you selected thousands of files.