Could you recommend a program for editing a hero's avatar?

To edit, you first need to unpack the hero portraits.
They are all packed in the game's .lod archives; you can unpack and view the archive contents
using the MMArchive program.
I'm currently working on editing the portraits of all heroes, both original and new.
I'm also searching for and compiling thematic graphics for the hero characters.
There are also several patches for displaying an enlarged hero portrait, but
they are not quite polished and only work with SOD + Hd mod.