the problem with editing in picasa is that it's algorithm to save the photo seriously compresses it, so unless you really don't care that you lost a whole bunch of information with each time you save in picasa I really wouldn't. I do still use it, to do quick and dirty edits for stuff that is going on the web (going to be compressed down low and resized anyway) but I save as a new file, not over my clean original. Actually working on a copy not an original is good practice just in case something goes wrong.