If you use sharpening it can cause an artefact along edges, especially in small images as used on this Board.
A technique for removing these artefacts is
flatten your image
create a new layer
set its blend mode to darken
select the clone tool
set the master size to about 2-5px
set the hardness to 0%
hit TAB to remove the menus
enlarge the image to around 500%
go to the left hand edge of the artefact
select the source from just above the artefact
run the clone tool along the artefact
practise, practise, practise and fine tune to the way you want it
