Solved by ptrblck in post #2 
              
              
                The first conv layer: 
nn.Conv2d(244, 244, kernel_size=3, stride=1, padding=1)

expects the input to have 244 channels, since in_channels=224. 
If you are passing an input with a single channel, change in_channels to 1: 
nn.Conv2d(1, 244, kernel_size=3, stride=1, padding=1)