[Question] How to chain convolutional layers? • /r/MachineLearning

The input is 3D, not 2D - (height, width, n_channels). Typical images are RGB (3 channels), though if you work with gray scale there is only one "color" channel. In either case you are simply making a 3D - 3D transformation. Note that this is per image, in practice you use minibatches so it is really 4D - 4D. Typical orderings are bc01 (batch size, channels, width, height) or c01b (channels, width, height, batch size).