plotly_IMAGE returning an empty file in RStudio

[jackparmer]

To replicate:

fig <- get_figure("Adriano.Santos", 0)
plotly_IMAGE(fig, format = "png", out_file = "output.png")

Seems like an issue with the R client, because these image endpoints are working:
https://plot.ly/~Adriano.Santos/0.png
https://plot.ly/~Adriano.Santos/0.jpeg

[yankev]

So it seems like it works for a simple example:

figure <- plot_ly(data = iris, x = Sepal.Length, y = Petal.Length, mode = "markers")
plotly_POST(figure)
gf<-get_figure("kevintest",41)
plotly_IMAGE(gf, format = "png", out_file = "output.png")

Though I've also taken a look at the result of the plotly_IMAGE call (ie: request) for the plot with the issue and I get the following response:

Response [https://api.plot.ly/v2/images]
  Date: 2016-03-04 16:21
  Status: 200
  Content-Type: image/png
<EMPTY BODY>

[yankev]

Update:
I played around with the REST API call a bit, and it seems that if you set scale=1, everything seems to work fine.
ie:

plotly_IMAGE(fig, format = "png", out_file = "output2.png", scale = 1)