Fix iPhone png FixPngDroplet - ModMyi - Wiki

I found the tutorial above, but I don't understand if it converts the file or replicates and converts a copy. If it makes a copy and replicates it, great. Then it is in a workable format and I still have an original that I can use as a backup. If it doesn't make a copy, great. Then I can still use the image in GIMP or iPaint or something. Finally my point: can it do the process in reverse? or is there even a need for it? If the drag and drop .app reorders or modifies the PNG chunking system, does it need to "undo" the process after I have modified an image? and if it doesn't, do I then just SFTP the new file to my phone?