Editing icons in AppWizard project

I want to change the icons in my project from those generated by the appwizard - the icon in the top left corner of the mainframe window and the top left of each child window, but if I edit and save the icons and then run my program, they still remain the same. Could somebody please tell me what I'm doing wrong?

The wizard generates 32x32 icons and 16x16 icons. Did you change both of them? When the type of problem you describe occurs, it's usually because the person forgot to the the 16x16 icon.

Thank you!