knitr::include_graphics for pdf_document

[mczek]

I'm having trouble getting my own .png files into the pdf output. I downloaded the example zip file and tried to use knitr::include_graphics to import the image, but it didn't work. There is a blank space in the PDF and the caption is shown, but not the image.

I have attached a reproducible example in a zip file. This issue is in both CRAN and Github versions. I also tried saving the image in various places, but none worked.

bookdown-demo-master replicate.zip