JFIF APP0 marker and UTF8

Hi everybody,

First, be tolerant with my english, it's not my mother tongue :smiley:
Secondly, I discovered MP3Tag recently and it seems to be a (very) good app ! Thanks to Florian for his development.

Finally, the reason of my post :
In past, I've coded a little tool to manage my MP3's library with, among other things, the APIC tag reading. Using MP3Tag, I decided to move ID3v2.30 tags (which use ASCII or UTF16 standards) in ID3V2.40 format (which use UTF8 unicode standard). Using my tool, now, I have a problem to read pictures.
After decoding files, I noticed than JFIF APP0 marker is now encoded in a four-bytes format (0xFF00E000) instead of a two-bytes format (0xFFE0) !

Is-it normal ?

Here, APIC tags examples of a same file in various formats :

ID3v2.30 - ISO-8859-1 and UTF16 :

ID3v2.40 - UTF8 :