1. First, we open any version of ps and enter
2. We create a picture with a layer size of 1*1 pixels. This size determines the size of the grid. If 1 pixels is not enough, 2 will increase or decrease in turn, and we will test the size we need.
3. Select the pencil tool, with 1-2 pixels, and cross the grid pattern
4. Select-Edit-Define the pattern, which is easy to manage by naming. Open the picture you need to add the grid, select-Edit-Fill-Select the pattern-Select the pattern you made
5. Finally, our effect-Preview.