score:7

Accepted answer

Well if you just want to have an image in the middle of the circle try this:

/* Create nodes */
var node = vis.selectAll("g.node")
    .data(json.nodes) // get the data how you want
    .enter().append("svg:g")
    .call(node_drag);

/* append circle to node */
node.append("svg:circle")
    .attr("cursor","pointer")
    .style("fill","#c6dbef")
    .attr("r", "10px"})

/* append image to node */
node.append("image")
    .attr("xlink:href", "https://github.com/favicon.ico")
    .attr("x", -8)
    .attr("y", -8)
    .attr("width", 16)
    .attr("height", 16);

You can also append a title, some text... See the documentation of selection.append(name) for more info.

score:0

For Dynamic Image, you can keep the image in local and using image name you can use the dynamic image from the local.

For making circle, you can use :

 var groups = node.enter().append("g")
        .attr("class", "node")
        .attr("id", function (d) {
            return d.entityType;
        })
        .on('click', click)

    groups.append("circle")
       .attr("cursor", "pointer")
       .style("fill", function(d) { return color(d.entityType); })
       .style("fill", "#fff")
       .style("stroke-width", "0")
       .style("stroke", "#ddd")
     .attr("r", 20);

Here, d.entityType will be the name of the image example : favicon.png

groups.append("image")
       .attr("xlink:href",function (d) {
            return "../assets/images/"+d.entityType+".png";
            })
        .attr("x", -14)
        .attr("y", -15)
        .attr("width", 30)
        .attr("height", 30)

If you want to add text inside the circle, you can use :

groups.append("text")
        .attr("dy", 18)
        .style("font-size", "2.5px")
        .style("text-anchor", "middle")
        .style('fill','#000')
        .attr("refX", 15)
        .attr("refY", -1.5)
        .text(function (d) {
            return d.entityName;
        });

Related Query

More Query from same tag