problems with pixmaps widget

[Flavio Alberto Lopes Soares <engenharia3 maqplas com br>]

Hello,

I have a problem with widget pixmaps, I need change the picture in a
pixmap widget in some moment in my application, but I don't know how to
make this, I think to copy x & y coordinates and other properties of
this pixmap, destroy it and re-create it with new picture with old
properties, but I don't know to obtain these data (these data are placed
in some place in GtkWidget struct ?), 
please help, I don't know to do.

Thanks for any help

Flavio Alberto