Re-Skin IMPOSIBLE?

[ I am useing Paint.Net ]
ok i go to my physgun mask texture.
I edit it.
click save, it AUTO CLOSES.
i open back up.
it is UNCHANGED.
Help.

Because you’re using the newer version of Paint.net.
Nem’s Plugin doesn’t work with the update.

Just go download an older version from somewhere else.
I suggest this one