A problem with background color of predicted images.

[Panverson]

Hi!
I fed my own dataset to train the model. The shape of each image in my dataset is 48 * 48 * 1, My images are not binary images but gray images with their value in [0.0, 1.0].
I noticed that the backgroud color of x[6:], y_hat are different from each other, and the ground-truth imagey.

Would you please help me explain the reason for the issue?
Thanks.