If you want to edit a placed image, e.g. by sharpening or recoloring the image, you can directly use the Photos.app image editor.
Open image Editor
Double-click on the image to be edited
In the image editor, you can postprocess your image
Apply the processing by clicking on the "Done" button
The picture is automatically updated in the background, maybe it is only after 1-2 sec on the screen to see, you can still continue to work normally.