[R-pkg-devel] Compact pdf warning

Hi,

I receive the following warning when I check my package:

checking sizes of PDF files under ?inst/doc? ... WARNING
? ?gs+qpdf? made some significant size reductions:
?? ? compacted ?gwqs-vignette.pdf? from 458Kb to 162Kb
? consider running tools::compactPDF(gs_quality = "ebook") on these files

For this warning I tried to add the option "--compact-vignettes=both" in the build source package R CMD build additional options but it did not work. When I use the tools::compactPDF(gs_quality = "ebook") command it is able to create the compacted pdf but then when I build the package then it rebuilds the vignette and the size is still the before one. Do you have any suggestion?

Thanks in advance,
Stefano