[snielson]

I use Paint.net for simple tasks like those you listed. I paid $10 for it in the Microsoft store but I think you can get it for free from the website.

[dokyun]

Paint.net isn't free software, it's proprietary freeware. It used to be free a long time ago, but the author is a tool and made it closed source because people were creating other versions of it.

[UncleSlacky]

Pinta is a free reimplenetation: https://www.pinta-project.com