Exporting R graphics into Word without losing graph quality
From: Duncan Murdoch...
Don't use a bitmap format (png).
I disagree. Each vector format comes with its own problems.
Don't produce your graph in one format (screen display), then convert to another (png). Open the device in the format you want for the final file.
Agreed.
Use a vector format for output.
Why? Sure, that's good advice in the ideal (pdflatex) world, but not necessarily the best of advice for Word users.
I don't know what kinds Word supports, but EPS or PDF would likely be best; if it can't read those, then Windows metafile (via windows() to open the device) would be best.
None of these works well, if at all, in my experience with Word.
Don't use Word.
Some of us don't really have a choice.