Thanks for posting this Pepe. Paint is a good option because everybody already has it (on Windows anyways).
At some point I’ll post a quick howto on Image Resizer. It’s a lot fewer steps, and works in bulk.
EDIT: guide is posted here. If Pepe doesn’t mind, this will eventually turn into a series of how-to guides… to that end, I added a cross reference at the start of your post.