gan design with graph

doc/design/gan_api.md

@@ -28,8 +28,8 @@ In our GAN design, we wrap it as a user-friendly easily customized python API to
 | Repmat op (done)          | ?                 | N (Cond) |
 
 <p align="center">
-<img src="./test.dot.png" width = "90%" align="center"/><br/>
-The overall running logic of GAN. The black solid arrows indicate the forward pass; the green dashed arrows indicate the backward pass of generator training; the red dashed arrows indicate the backward pass of the discriminator training. The BP pass of the green (red) arrow should only update the parameters in the green (red) boxes.
+<img src="./test.dot.png" width = "50%" align="center"/><br/>
+The overall running logic of GAN. The black solid arrows indicate the forward pass; the green dashed arrows indicate the backward pass of generator training; the red dashed arrows indicate the backward pass of the discriminator training. The BP pass of the green (red) arrow should only update the parameters in the green (red) boxes. The diamonds indicate the data providers.
 </p>