Adjust display of result image

Signed-off-by: Jael Gu <mengjia.gu@zilliz.com>

README.md

@@ -31,7 +31,7 @@ import towhee
           .show()
 )
 ```
-<img src="./result1.png" height="45px"/>
+<img src="./result1.png" width="400px"/>
 
 *Write a same pipeline with explicit inputs/outputs name specifications:*
 
@@ -47,7 +47,7 @@ import towhee
           .show(formatter={'path':'video_path'})
 )
 ```
-<img src="./result2.png" height="100px"/>
+<img src="./result2.png" width="400px"/>
 
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