Many thanks for the Tutorial... I read it some months ago but couldn't find a suitable subject until recently!
May I make a suggestion? Could you add a note (for us newbies!) just before "Save the file as a .PNG..." stating that Paint.Net will want to flatten the picture before saving, and not to forget to do a Ctrl-Z (Undo) after saving to unflatten it before carrying on (or have I done something wrong somewhere?)
Here's my humble effort, hope you like it!
Thanks again!