[eluser]v1ctoria[/eluser]
I finally found the solution!!
This is something strange and I don't think I was wrong to do that.
In my autoload file, I was including the image_lib.
This as a direct consequence to load the library with the default parameters which are set into the image_lib library file.
I tried to erase the library call from the controller because I knew that I was calling it from the autoload. After new install and tests, I realize the consequence with the autoload.
I think the core must check if new config has been set as parameter when calling a function.
Anyway, I hope this 2 days lost will help other people.
Thanks a lot.