Img2Ps: convert a PNM or JPEG image to Postscript-2
imgtops2 is a utility for converting images to PostScript Level 2. Level 2 supports more efficient encoding of image data than the original PostScript standard, so the files produced by imgtops2 are significantly smaller than those made by pnmtops of the PBMPlus package or convert of the ImageMagick package. This is especially true of JPEG files, which Level 2 can handle directly but Level 1 implementations must first decompress. Level 2 PostScript has been the standard for almost a decade now (Level 3 is actually out now), so nearly all printers support it.
imgtops2-0.1 can be downloaded from the GnuWin32 download page.
General Installation Instructions