If you edit a .jpg file outside of your digital camera, you will probably need to convert it back into a .jpg file the camera supports (DCF compliant).
You only need to do this if you want to transfer your edited pictures back into the camera's SD card for viewing on the camera.  

Here is the best program I have found so far.  It only creates a 800x600 version, but for your camera view, its usually big enough. The name of the program is "ImageCreator v1.5.3"
http://panasonic.net/avc/projector/software/imagecreator.html

The name of the file must also match the camera's format.  The best way to do this is to take a pic on the camera and see how it named it.  
Once you see how the camera likes it named, just make your edited pics match the format with a new #.