Update README.md

Author: csxmli2016

README.md

@@ -30,6 +30,7 @@ The first row is real low quality image(close-up in right bottom is the guided i
 
 ## IMDB results
 |      Input      | Guided Image | Bicubic |   Ours  |
+| :-----------: |:----:|:----:|:---------:|:----:|:---------:|:------:| -----:|:--------:|
 |   <img src='./imgs/IMDb/1_2.jpg'>  |<img src='./imgs/IMDb/1_1.jpg'> | <img src='./imgs/IMDb/1_3.jpg'> |   <img src='./imgs/IMDb/1_4.jpg'>    |
 
 [More IMDB resutls can be found here.](http://csxmli.xin/GFRNet/)