xfce – change panel icon size
in File: ~/.config/gtk-3.0/gtk.css eg: #pulseaudio-button image{ -gtk-icon-transform: scale(0.7); } #xapp-status-plugin-5 image{ -gtk-icon-transform: scale(0.7); } #weather-11 image{ -gtk-icon-transform: scale(0.7); } Then restart panel: xfce4-panel -r