qpdf: image /IIm1 on page 1: optimizing image reduces size from 2392 to ...
qpdf: image /IIm2 on page 1: optimizing image reduces size from 2134997 to ...
qpdf: image /IIm3 on page 1: not optimizing because unable to decode data or data already uses DCT
qpdf: image /IIm4 on page 1: not optimizing because DCT compression does not reduce image size
qpdf: wrote file a.pdf
