It is simple to fade edges using photoshop. You can follow the following steps.   Apply any preferable selection method to make a selection near your desired edge. Now, click Select- Modify-Feather from the top options bar. Now you will get a new window & place 25 in the Feather Radius field & then select Ok. Then select Image- Adjustments – Curves. Select the center point of the curve & attach the anchor point. Then move it to fade your edges.