Issue album art image and ID3v2.4 UTF-8

[DetlevD]

@Hugh

... Current Issue ... Default Mp3tag settings for Mpeg is ID3v2.4 UTF-16. ...

This setting is not possible within Mp3tag.
Possible settings are ID3v2.3 UTF-16 or ID3v2.4 UTF-8.

@Hugh

... But most of all, my Mp3 files are embedded with album art work but not showing on my smartphone. ... Instead of trying to use Mp3tag, I'm using iTunes to embedded my album art work. It turn out to be fine no problem showing album image on my smartphone. ...

Which tag-type is supported by iTunes ... ID3v2.3 UTF-16 or ID3v2.4 UTF-8?

It is rather not expectable, that popular devices support reading of ID3v2.4 tag-type, ...
therefore I do not believe, that your Android can understand the ID3v2.4 tag-type.

You should setup your Mp3tag to read, write, delete ID3v2.3 tag-type.
Additionally remove possible existing APE tag-type from the media file.
Note: The APE tag may hold one or more pictures, which you may save to disk, before removing the APE tag.
Note: Mp3tag treats the APE tag with higher priority than the ID3v2.x tag-type.

After removing the APE tag from the media file, you should setup your Mp3tag to never use the APE tag again, so set all APE related checkboxes to "off" in the dialog "Mp3tag Options/Tags/Mpeg".

DD.20150827.1015.CEST