I wrote a program for this back in '07 in VB. It was called MDKPhotoLab. I would arrive at an event withmy camera, laptop, Epson PictureMate Photo Deluxe, and a small router. I set the eye-fi card up to upload images locally to the laptop into an inbound directory. The program would monitor the directory for new files and when one arrived it would open it, add a logo on the bottom, send the picture to the printer and then move the picture to a processed directory. It would not modified the saved file other than moving it. (No loss in quality or ratio.) It was specific to my setup and never tested anywhere else. I only printed 4x6's to the Picture Mate and only used JPG's (since that is all the eye-fi would transfer.)
Well I changed laptops about a year ago and couldn't find my vb install disks to make updates. Still have the source code and forms but have gotten busy with other projects now. I would write updates but these summer months have been busy for me with my photography business and the eye-fi card isn't used that much anymore because of only being 2GB in size. I shoot with 8GB cards now. Don't know why eye-fi's largest card is still only 4gb when 16gb & 32gb are becomming common.