yes, so the width and height changes along with the input image size.
Typically, we cound define a function to calculate the size automatically.
def num_flat_features(self, x):
    size = x.size()[1:]  # all dimensions except the batch dimension
    num_features = 1
    for s in size:
        num_features *= s
    return num_features

then we can use

x = x.view(-1, self.num_flat_features(x))
instead of
x.view(-1, 1655)