Solved by Nikronic in post #2 
              
              
                Hi, 
I think easiest way is too define a super class and change only first layer, something like this: 
import torch
import torch.nn as nn
import torchvision

class MyVGG(nn.Module):
    def __init__(self, in_channel=1):
        super(MyVGG, self).__init__()
        
        # use PyTorch implementa…