Available in pre-release 3.7
To compress a PDF using SumatraPDF from command-line:
SumatraPDF clean -gggg -e 100 -f -i -t -Z foo.pdf foo-compressed.pdfThis uses most aggressive compression flags.
For explanation of all flags see SumatraPDF clean.
If a PDF file is uncompressed, the compressed version should be smaller.
If a PDF is already compressed, this will have little effect.
You can also decompress PDF.