update zh-cn/application-dev/reference/arkui-ts/ts-basic-components-image.md.

Signed-off-by: LiAn <lian15@huawei.com> 
Signed-off-by: NLiAn <lian15@huawei.com>

zh-cn/application-dev/reference/arkui-ts/ts-basic-components-image.md

@@ -320,7 +320,7 @@ struct ImageExample3 {
             .onError(() => {
               console.log('load image fail')
             })
-            .overlay('\nwidth: ' + String(this.width) + ' height: ' + String(this.height), {
+            .overlay('\nwidth: ' + String(this.widthValue) + ' height: ' + String(this.heightValue), {
               align: Alignment.Bottom,
               offset: { x: 0, y: 20 }
             })