Hi @ptrblck,
I tried both return x, target  and return x[0],x[1],x[2],target and the error I got was -
TypeError                                 Traceback (most recent call last)
<ipython-input-83-e03efae61dea> in <module>
----> 1 model, history_model = train_model(model, criterion, optimizer, exp_lr_scheduler, num_epochs=10)

<ipython-input-47-f9a9be299e22> in train_model(model, criterion, optimizer, scheduler, num_epochs)
     34                 # track history if only in train
     35                 with torch.set_grad_enabled(phase == 'train'):
---> 36                     outputs = model(inputs)
     37                     #print(outputs.shape)
     38                     _, preds = torch.max(outputs, 1)

/opt/conda/lib/python3.6/site-packages/torch/nn/modules/module.py in __call__(self, *input, **kwargs)
    491             result = self._slow_forward(*input, **kwargs)
    492         else:
--> 493             result = self.forward(*input, **kwargs)
    494         for hook in self._forward_hooks.values():
    495             hook_result = hook(self, input, result)

TypeError: forward() missing 2 required positional arguments: 'image2' and 'image3'

in both the cases.