You can use the following command to reshape to a 200x200x1 array.
data = data.reshape(-1,200,200,1)
You can also transform your (n_samples,200,200,1) shaped data into a dataset and batch it. It should fix your dimension problem.
You can do that by using the following command: tf.data.Dataset.from_tensor_slices((inputs,outputs)).batch(BATCHSIZE)