2. Next, press the shortcut key "Ctrl+j" to copy the background layer.
3. Next, select "Crop Tool" in the left toolbar, and set the width and height according to the red arrow in the figure.
4. Then select "Color Range", use the eyedropper tool to absorb the blue background of the layer, change the background color to white, and press the shortcut key "Ctrl+delete" to fill it.