Batch mode Grayscale converter

I want to be able to point to one folder, and have all the jpgs in that folder and all its subfolders converted to grayscale, and saved over the top of the original files. Needs to be an option for "include subfolders", but essentially all the jpgs in what I select need to end up as grayscales. Quick and easy. Filesizes should be reduced, because compression will be maintained. ## Deliverables Needs to be easy to use GUI, with ccheckbox for considering subfolders. Installs on Windows 7 or Vista. Samples are attached for me to check output. * * *This broadcast message was sent to all bidders on Tuesday Jan 24, 2012 3:40:51 PM: Please see slightly clarified requirements, as well as sample images posted. I am in need of a quick resolution to this; please respond again if you are able to fill this need quickly. thanks!