I used this for it: http://victorx.eu/BitmapPlayer.htm To imagine we can that with moving images in the browser now, well, whoa.
[1] http://arss.sourceforge.net
Still there is active research on reconstructing signals from only the Fourier magnitudes (under several assumptions). This is called the 'phase-retrieval problem'. http://en.wikipedia.org/wiki/Phase_retrieval
There's also the possibility the spectrographic image itself might be a lossy representation of the actual frequency domain data, in which case you won't get a perfect result back out. Probably recognisable though.
If I had time I'd do some flubbing with octave/scipy and demonstrate it, but alas, the margins of this weekend are too small, etc, etc.
[1] https://en.wikipedia.org/wiki/Short-time_Fourier_transform#I...
His newest album Syro also has less aggressive tracks, but it seems to not be on YouTube.
Just a personal preference!