Never mind, I find another solution using some scripting. Sorry for the noise.
Hi Nikkho, I recently discovered this great gem of a tool and am quite happy with the results. I start FileOptimizer (FO) from my file manager passing selected files to command line so FO automatically starts optimizing. So far so good. However, I use a virtual desktop program (PowerPro), which has to monitor all running programs by its nature. When FO starts optimizing PNG files, the PNG plugins take a long time (despite a very powerful CPU), and for some reason it completely slows down my VDesk...