fixed 39f402a8 from https://gitee.com/HelloCrease/docs/pulls/16127

update zh-cn/application-dev/ui/ui-js-components-stepper.md.
Signed-off-by: NLiAn <lian15@huawei.com>
Signed-off-by: NLiAn <lian15@huawei.com>

zh-cn/application-dev/ui/ui-js-components-stepper.md

@@ -186,7 +186,7 @@ text{
 }
 ```
 
-![zh-cn_image_0000001234130975](figures/zh-cn_image_0000001234130975.PNG)
+![zh-cn_image_0000001234130975](figures/zh-cn_image_0000001234130975.png)
 
 
 ## 添加事件