Legal questions - Infos inside Image after / within Gimp

Hello - I am new here and like to know how it works in detail, that all is fine.

1. I am generating an image in Firefly 2.

2. I am downloading the finished image. Firefly is including the infos inside the image who has created it.

So far so good

3. I am opening the image in Gimp and change the size to 2:1 with copy and paste.

4. I am saving the new image again and refill it in Firefly 2, so that i have 2:1 Format.

5. After refill i download the new 2:1 image with the creator infos inside.

So far so good

Now the question is: When editing the image generated from myself in Gimp ( copy paste ) - Which infos must be included in the "final image" ? Can i sell now the image on my own website ? Do i need anything to know, so that all is legal and stress free ?

A little help would be great.

Thanks

Dirk