Current questions and answers regarding the map editor.

I changed the icons, but the map won't launch. Try to remember what you did.

Initially, the map launched, but the textures were compressed, as you said. Then, I created new textures, replaced them in the file, and after that, the game started giving an error: "Hero 'Storm_Caller' has no visual part."
I didn't do anything else.

Added 35 minutes later

Add the line and delete the Creature folder in GameMechanics; the error is somewhere there.

I added the line, and it really worked. I somehow didn't think it could be due to the "Combat visual" parameter.
I replaced the DDS images you sent; the background is transparent, and everything looks great. Did you add an alpha channel to the original image to get a transparent background?
I cut out the background, but it still appeared during export.

And the Creature folder doesn't affect anything; the problem was really in "Combat visual" and in the error in the texture name you specified.

Thank you for your time and help