Julzology

I'm not sure if this is a windows problem or a Paint.net problem. The picture I'm editing came over from my phone rotated so the first thing I had to do is rotate it clockwise. Then I cropped it. Then I saved as .jpg. But it reverts back to the rotated image. How do I get it to stay rotated in the right direction. I'm helping my husband who is an artist send some of his artwork for an exhibition/contest he's entering. Thanks for any advice.