Solved by vmirly1 in post #2 
              
              
                You can apply the reshape to the tesnors that comes out as batches from the train_loader. For example: 
batch_x, batch_y = next(iter(train_loader))

batch_x = batch_x.reshape((self.ncrops*batch_size, self.in_channel, self.img_cols, self.img_rows))