Use nodeStyleFunction to dynamically change the node settings. Example:
http://jsfiddle.net/1rydhqeg/2/
style: {
nodeStyleFunction: function (node) {
node.image = "https://zoomcharts.com/dvsl/data/net-chart/friend-net/" + node.id + ".png";
if (zoom < 1.5) node.label = ""; // this line here removes the label if zoom is to small
else node.label = node.id; // put the label back if zoom is enough
}
},
events: {
onPositionChange: function(){zoom = chart.zoom(); chart.updateStyle();} // update the style, when the zoom/position is changed
}