This IS the original. Trust me, I've had this picture for like 10 or 15 years saved on my computer and the pants are undone, there are no other version.
Here's another picture that seems to be from the same day, also with his pants unbuttoned:
I don't think there's anything sexual about this picture. Michael's pants felt too tight, so he unbuttoned them for comfort, no big deal.
As he did here:
Not really out of character for him, there's even a close-up on his unbuttoned pants in the What More Can I Give video, so clearly Michael didn't mind.
Now THIS however was definitely not done for comfort: