Reduce PDF file size

sudo apt install ghostscript

Usually it’s already there.

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/prepress -dNOPAUSE -dQUIET -dBATCH -sOutputFile=compressed_PDF_file.pdf input_PDF_file.pdf

add the correct path of the input and output PDF file.

The dPDFSETTINGS parameter is what determines the compression level. It seems jpg is not supported, though I remember I could select that in Adobe Acrobat and have complete control over file size. Still it’s better than nothing, and way better then having a monstrous OS.

dPDFSETTINGS	Description
/prepress (default)	Higher quality output (300 dpi) but bigger size
/ebook	Medium quality output (150 dpi) with moderate output file size
/screen	Lower quality output (72 dpi) but smallest possible output file size