I have a picture that I am trying to feather the egdes. I am using the marquee tool with the feather option to select a portion of the picture. When using thw feather option, the marquee corners edges are rounded. I need them to be square. Is there a way to force the feather marquee tool to have square corners?
A feathered marquee is represented by rounded corners. If you feather a selection you will not get perfectly square corners, but the lower the feather value, the closer to square they will be.
As Jim mentioned, you can't feather a marquee selectionand make it appear perfectly square. You can try adding an Inner Glow to the selection in a color that martches the canvas.