Hi again Cristian,

Thank you so much for your help !
I wish I could give you a hundred UT stars !

Wow !
I was sure that would run faster in C, but the difference was really huge !
An Image Processing that was taking 3.40 seconds now is taking 0.018 seconds !

A difference of performance of 189 times !
The process became really instantaneous !

Lockbits permits to make all kinds of image manipulations, and from now on so many possibilities came, that I must confess that I need to think again about it all.

Again, thanks very much for your great help.

Regards

Cesar