!7304 image文档示例优化-二期

Merge pull request !7304 from 徐蕊w/master

zh-cn/application-dev/reference/apis/js-apis-image.md

@@ -892,8 +892,6 @@ let opts = { editable: true, pixelFormat: 3, size: { height: 4, width: 6 } }
 image.createPixelMap(color, opts, (pixelmap) => {
     pixelmap.release().then(() => {
 	    console.log('Succeeded in releasing pixelmap object.');
-    }).catch(error => {
-	    console.log('Failed to release pixelmap object.');
     })
 })
 ```
@@ -1637,8 +1635,6 @@ let packOpts = { format:"image/jpeg", quality:98 }
 const pixelMapApi = new ArrayBuffer(400);
 imagePackerApi.packing(pixelMapApi, packOpts, data => { 
     console.log('Succeeded in packing the image.');
-}).catch(error => {
-	console.log('Failed to pack the image.');
 })
 ```
 
@@ -2070,8 +2066,6 @@ release(callback: AsyncCallback\<void>): void
 ```js
 img.release(() =>{ 
     console.log('release succeeded.');
-}).catch(error => {
-    console.log('release failed.');
 }) 
 ```