12-12-2017, 07:12 PM
tsk...a Nikon D5300 - do not give up the day job 
Use the clone tool see: https://docs.gimp.org/en/gimp-tool-clone.html
Using a fuzzy brush, set the clone tool to alignment mode. Ctrl-click and fill in first one side, then the other.
There is just enough at the top to ctrl-click the division and clone in the boundary between light and dark.
example: https://i.imgur.com/KBwENQm.jpg
Use the clone tool see: https://docs.gimp.org/en/gimp-tool-clone.html
Using a fuzzy brush, set the clone tool to alignment mode. Ctrl-click and fill in first one side, then the other.
There is just enough at the top to ctrl-click the division and clone in the boundary between light and dark.
example: https://i.imgur.com/KBwENQm.jpg