The problem is probably because in your 3rd conv layer is expecting 64 channels, but you’re only giving it 3.

self.feature = nn.Sequential(
        nn.Conv2d(3, 64, kernel_size=3, padding=1),
        nn.ReLU(True),
        nn.Conv2d(64, 64, kernel_size=3, padding=1),
        nn.ReLU(True),
        nn.MaxPool2d(kernel_size=2, stride=2, dilation=1),

        nn.Conv2d(64, 64, kernel_size = 3, padding = 1), # <-- replace your line with this
        nn.ReLU(True),
        nn.Conv2d(64, 64, kernel_size = 3, padding = 1),
        nn.ReLU(True),
        nn.MaxPool2d(kernel_size = 2, stride = 2, dilation = 1),
       ...