Change PDF Resolution
Get Ghostscript and replace <DPI>
gs -sDEVICE=pdfwrite \ -dCompatibilityLevel=1.4 \ -dPDFSETTINGS=/screen \ -dNOPAUSE -dQUIET -dBATCH \ -sOutputFile=out.pdf \ -r<DPI> \ in.pdf
Get Ghostscript and replace <DPI>
gs -sDEVICE=pdfwrite \ -dCompatibilityLevel=1.4 \ -dPDFSETTINGS=/screen \ -dNOPAUSE -dQUIET -dBATCH \ -sOutputFile=out.pdf \ -r<DPI> \ in.pdf