When knitting to word_document2, when using knitr::include_graphics on a pdf shows "The picture can't be displayed." where the image should be. It does work for .png.
```{r pressure, fig.cap = "testing", echo=FALSE}
plot(pressure)
```
```{r, include = FALSE}
png("pressure.png")
plot(pressure)
dev.off()
```
```{r, include = FALSE}
pdf("pressure.pdf")
plot(pressure)
dev.off()
```
```{r pressure-png, fig.cap = "testing png", echo = FALSE}
knitr::include_graphics("pressure.png")
```
```{r pressure-pdf, fig.cap = "testing pdf", echo = FALSE}
knitr::include_graphics("pressure.pdf")
```