PS image gradient

First, I will show you an image:

I want to make the image gradient without changing the color of the intermediate image. Next, let me explain my ideas.

Select the middle part of the image and copy it into a layer.

The specific operation is to use the magic wand for reverse selection and select the intermediate part:

Then I'm copying a layer to use it as a separate middle layer.

Then we will make the source image layer gradient style:

Note: layer 0 is selected, and Layer 1 is only the middle layer.

Save it as a PNG image.

PS image gradient