It did something...
I tested this app and it needs some major improvements. If you want to view the metadata of a pic install homebrew on your mac and do a brew install exiftool. Then exiftool -list image.jpg and you will see all the metadata. I did this and then ran this purge software. I listed everything again and it did purge a few things but added MORE!! Rediculous. If you have followed these instructions, do a exiftool -all= image.jpg to really purge your metadata from your pic. Additionally, you can set up a script and remove ALL metadata from ALL pictures on your entire computer with the cli too. Also, check out fotoforensics.com for a prettier (web based) look at your metadata.
John Galbraith about EXIFPurge