Sets the default size of each tool bitmap. The default bitmap size is 16 by 15 pixels. On GTK, the toolbar will automatically re-size itself to fit the bitmaps you add, but on MSW, this call is required if you use bitmaps bigger that the standard. It won’t hurt anything to call it on GTK.
tsize = ( 32, 32 )
self.tb.SetToolBitmapSize( tsize )