It's hard to see for me because it's dark, so I'm not sure. How did you put image on page?
If you dropped image directly on page, then it would be part of the image.
If you dropped image onto a Rectangle, then you can double-click on the Rectange to enter background image edit mode to increase size of image so "harsh line" can be masked out. Press Esc or click away from image to exit background edit mode.
Otherwise, try opening the Layers Panel to see if there's some other object getting in the way.