[quote=124106:@Paulo Vargas]You did not need to have lost so much time with it my friend.
Tanks a lot Michel ![/quote]
You are welcome, Paulo. But I was rewarded by the discovery.
And it is not finished. I took the same program over Windows, and guess what ? A picture loaded into the program gives precise color values !
Conclusion : the bug pertains to the Macintosh platform. For once, Windows works better
I filed a bug report :
35021 - Mac OS X bug loading colors from picture file