Howto to make (compact) pdf / png files with scanned pictures

Including scanned pictures into Latex / pdf documents often blows up the document to a not acceptable size.

Here some advice how to avoid this.

• Scan the original using xsane with 150 dpi resolution to jpeg format (e.g. figure.jpeg).
  Adjust the brightness such that white background is really white without shades.
• Convert the jpeg file with the help of the following tool:

  jpeg2ps -o figure.ps -h figure.jpeg 
  

  However using pdflatex directly is even more economic.