AssertionError when running notebook

[ghost]

I'm getting the following error when running the notebook. I ran it both with jpg as well as png files from different sources and in different aspect ratios

AssertionError                            Traceback (most recent call last)
<ipython-input-4-544c57e7cc8b> in <module>()
    102         display.display(plt.gcf())
    103         display.clear_output(wait=True)
--> 104         for k,(HR,_) in enumerate(model(ref_im,**kwargs)):
    105           if(show_intermediate_images):
    106             if(k==0 or (k+1)%10==0):

1 frames
/content/pulse/loss.py in __init__(self, ref_im, loss_str, eps)
      5     def __init__(self, ref_im, loss_str, eps):
      6         super(LossBuilder, self).__init__()
----> 7         assert ref_im.shape[2]==ref_im.shape[3]
      8         im_size = ref_im.shape[2]
      9         factor=1024//im_size