Solved by ptrblck in post #2 
              
              
                The model.features[0].weight parameter has a shape of [4, 3, 3] so one dimension is missing. 
nn.Conv2d defines the weight parameter as [out_channels, in_channels, height, width]. 
Based on the current code, I guess that the number of in_channels is missing? 
If that’s the case, you could unsqueeze …