[copy and paste]

you just need to paste the object in as a new layer Ctrl+Shift+V instead of the standard paste

and when its in place, can use Layer tools to change some of the object properties or press Ctrl+M to flatten it

[how to merge two pics?]

edit: just remembered this

the key is to paste the portrait to the background as a new layer, dont save the portrait with transparent background, just highlight the portrait with magic wand, copy it and Ctrl+Shift+V onto the new background.

[How to remove watermarks?]

removing watermarks may violate copyright, but the method to do its the same for any kindof complex alteration to an image like airbrushing or removing a date stamp or artifact from a photo, using the clone stamp allready included in Paintnet. its not that difficult but can take some doing, depending how complex the background image is surrounding the water-mark

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