From the pandoc documentation I know how to insert an image
http://johnmacfarlane.net/pandoc/README.html#images
Now I want to align two images in the same row, h
One simple way is convert your file first to a .tex file, where you can adjust your image alignment with LaTeX command minipage or so. Then you could obtain your .pdf file running latex or pandoc in command line. See Pandoc Demos for example.