Hi there,
If the shape of data is [4096, 3, 64, 64], and if self.fc1 = nn.Linear(64, 100), then self.fc1(data) will consider the 64 rows of each image as 64 different feature vectors, and will output a tensor of size [4096, 3, 64, 100], transforming the 64 rows to 64 feature vectors of size 100.
Then, the tensor output might be shaped [4096, 3, 64, 10], which is probably the source of the error.
Did you want to flatten your data images instead ?