Plotly.d3 is undefined now

[stla]

Hello,

The example in the plotly book with the images appearing on hovering does no longer work. That's because Plotly.d3 is undefined in recent versions of plotly.js. This had been announced in the announcement of plotly.js v2.

So to make the example work, one has to include d3.js as a HTML dependency and do d3.select instead of Plotly.d3.select.