Here I need to fix the corner. Cropping won't work here.

But I can use the selection tool and copy the left fence.

Paste a new layer of the fence, position in place. I did it twice here.
notice the layer palette.

Add a layer. Use the selection tool to surround the edge for the new border.

Invert the selection so it look like this.
and fill it with a matching color.

Select-select none- to remove the marquee.
I want the date at the top to show, so I erase that area.

Merge visible and crop to the correct border width.

Like this. All fixed!