Add AudioAmplifier documentation image

gui/index.html

@@ -1407,6 +1407,7 @@ span.mainfunction {color: #993300; font-weight: bolder}
 	<div class=tooltipinfo>
 	<p>Amplify or attenuate a signal, or switch it on/off.
 		</p>
+	<p align=center><img src="img/ampschematics.png"></p>
 	</div>
 	<h3>Audio Connections</h3>
 	<table class=doc align=center cellpadding=3>