Generating spectrogram for band-pass filtered wav file python
Using scipy you can easily:


bandpass signals, for instance with scipy.signal.butter
obtain a spectrogram, using for instance scipy.signal.stft (or LTFAT, The Large Time-Frequency Toolbox (LTFAT) in Python)
scale the values of this 2D array so that each channel has values between $0$ and $1$
reshape the array into a $560\times 420$ grid, eg with scipy.ndimage.affine_transform or scipy.ndimage.geometric_transform
save the image, but I don't know the PCG format