Using Gtk+ 2, I could use the gtk-icon-sizes option like this:gtk-icon-sizes = panel-menu=32,32:panel=32,32:gtk-menu=32,32:gtk-large-toolbar=64,64:gtk-small-toolbar=48,48:gtk-button=32,32gtk-icon-sizes was deprecated and removed in Gtk+ 3.How do I change icon sizes in Gtk+ 3?
change icon sizes in Gtk+ 3 applications
gtk3