How to darken the four corners of a picture with gradient tool in PS?

1. Create two new layers on the original image, inject black on the top layer, and then add a mask on the black layer.

2. Merge the black layer mask and the second new layer.

3. Click the Elliptical Marquee Tool, enter the feathering value (as large as possible), and then draw a complete circle on the black layer.

4. Click the menu above to select -reverse (or reverse), and press the del key to delete the middle part.

5. The brightness of the four corners can adjust the transparency of the black layer.

6. Merge layers.