I cleaned all MP3 files in MP3Diags. I then used MP3Gain to set normalization and it made APE tags, but as I'd seen before the APE tags gave invisibility to the previous tags which is undesirable. How do I get both the APE tags and the MP3tag tags I wrote before not to be invisible?
You can't.
In MP3tag APE tags are displayed if present and selected to be read and all other tags are not displayed.
This is also documented:
The workaround would be to use a replaygain program that writes the data to ID3 tags instead of APE tags.
Or use a program that copies the contents of ID3 tags to APE tags when creating new fields.
I don't know why but now it works with the artworks in both windows and on Musicolet (though the tags didn't show up in MP3tags yesterday maybe I just need to turn off Read APE tags?). Must have been the detail work done that made these appear now when before they didn't appear. MP3Diags and all that. Everything looks good. I am just about to do a 14 hour normalized recording in Musicolet on my Samsung phone of an old Youtube playlist that has been long deleted, with new artwork and perfect tags. GREAT!
Use Foobar2000. It can scan for ReplayGain and simultaneously save data to APEv2, ID3v2 and ID3v1 tags when checkmarked. It has almost all the same options as Mp3Tag and almost the same scripting functions and syntax.
APE is the superior of the tag types. It goes at the end of the file, and consists of simple, mostly unambiguous key-value pairs, similar to FLAC, without complex mappings. It was the first tag type to be added in early Foobar 0.7/0.8.