Convolutional neural networks expect 4D input where the inputs are:
image_# x n_channel x width x height
So if you want to input 1 grey-scale image you would have to reshape your input image to 1x1x10x10. You can use .view() on a torch tensor to reshape:
a = torch.randn((10, 10))
print(a.size()) # torch.Size([10, 10])

a = a.view((1, 1, 10, 10))
print(a.size()) # torch.Size([1, 1, 10, 10])

Now the model should input the image without error.