PBM handles the following black&white formats:

    Sun icon file				reading	writing
    X10 and X11 bitmap file			reading	writing
    MacPaint					reading	writing
    CMU window manager format			reading	writing
    MGR format					reading	writing
    Group 3 FAX					reading	writing
    GEM .img format				reading	writing
    Bennet Yee's "face" format			reading	writing
    Atari Degas .pi3 format			reading	writing
    Andrew Toolkit raster object   		reading	writing
    Xerox doodle brushes			reading
    ASCII graphics					writing
    HP LaserJet format					writing
    GraphOn graphics					writing
    BBN BitGraph graphics				writing
    Printronix format					writing
    Gemini 10x printer format				writing
    Epson printer format				writing
    Unix plot(5) file					writing
    Zinc Interface Library icon				writing

PGM handles the following grayscale formats:

    Usenix FaceSaver(tm) file			reading	writing
    FITS					reading	writing
    Lisp Machine bit-array-file			reading	writing
    raw grayscale bytes				reading
    HIPS					reading
    PostScript "image" data			reading

PPM handles the following color formats:

    GIF						reading	writing
    IFF ILBM					reading	writing
    PICT					reading	writing
    Atari Degas .pi1 format			reading	writing
    XPM (X Window System ASCII pixmaps)		reading	writing
    PC Paintbrush .pcx format			reading	writing
    TrueVision Targa file			reading	writing
    HP PaintJet format				reading	writing
    Abekas YUV format				reading	writing
    MTV/PRT ray-tracer output			reading
    QRT ray-tracer output			reading
    Img-whatnot file				reading
    Xim file					reading
    Atari uncompressed Spectrum			reading
    Atari compressed Spectrum			reading
    NCSA Interactive Color Raster			writing
    X11 "puzzle" file					writing
    Motif UIL icon file					writing
    DEC sixel format					writing
    AutoCAD slide format			reading	writing
    AutoCAD DXB format					writing

PNM handles the following multi-type formats:

    Sun raster file				reading	writing
    TIFF					reading	writing
    X11 window dump file			reading	writing
    X10 window dump file			reading
    PostScript					writing