Update: update screen capture code and examples

.circleci/images/primary/Dockerfile

@@ -1,5 +1,5 @@
 # FROM golang:1.10.1
-FROM golang:1.22.3-stretch AS build
+FROM golang:1.23.2-stretch AS build
 # FROM govgo/go:1.11.1
 
 RUN apt update && apt install -y --no-install-recommends \

robotgo.go

@@ -366,11 +366,11 @@ func CaptureGo(args ...int) Bitmap {
 	return ToBitmap(bit)
 }
 
-// CaptureImg capture the screen and return image.Image
+// CaptureImg capture the screen and return image.Image, error
 func CaptureImg(args ...int) (image.Image, error) {
 	bit := CaptureScreen(args...)
 	if bit == nil {
-		return nil, errors.New("capture error")
+		return nil, errors.New("Capture image not found.")
 	}
 	defer FreeBitmap(bit)
 

screen.go

@@ -11,7 +11,6 @@
 package robotgo
 
 import (
-	"errors"
 	"image"
 
 	"github.com/kbinani/screenshot"
@@ -31,7 +30,7 @@ func GetDisplayRect(i int) Rect {
 		Size{W: w, H: h}}
 }
 
-// Capture capture the screenshot
+// Capture capture the screenshot, use the CaptureImg default
 func Capture(args ...int) (*image.RGBA, error) {
 	displayId := 0
 	if DisplayID != -1 {
@@ -54,9 +53,9 @@ func Capture(args ...int) (*image.RGBA, error) {
 
 // SaveCapture capture screen and save the screenshot to image
 func SaveCapture(path string, args ...int) error {
-	img := CaptureImg(args...)
-	if img == nil {
-		return errors.New("Capture image not found")
+	img, err := CaptureImg(args...)
+	if err != nil {
+		return err
 	}
 
 	return Save(img, path)