I'd also like to know how mosaicing is reversible, since it demonstrably reduces the total available amount of information from e.g. 20x20 = 400 RGB values to a single RGB value. This is not sufficient for text where you can start brute-forcing individual options because the search space is small and inputs can be reconstructed precisely, but I'd like to see an explanation why you think this is reversible for photos (even without noise added). I'd also like to know how you want to remove random noise applied to each mosaic block.
The mosaicing is supposed to be the security step here. The blur is optional eye candy not expected to remove further information.
In particular, if you claim that a face mosaiced with a large "pixel" size (e.g. so that the typical face is 5x5 "mosaic blocks" big), you're effectively claiming that you can perform facial recognition based on noisy 5x5 pixel images.
it doesn't matter though. as I've explained, it's far easier to come up with flawed schemes than prove them insecure. just because I can't explain why your specific scheme is insecure doesn't mean it stands a chance against real cryptographers.
Hence my suggestion to reduce a face to something like 5x5 blocks.
While I'm familiar with the crypto design problem, this is not a crypto algorithm. Sure, it can't be ruled out that someone in the future will find a way to do it, but the state of the art says that 5x5 pixels are not anywhere near enough to run face recognition.
And a solution that may be broken in the future is often much better than a solution that people don't use because it doesn't meet their needs, which in this case is not having fugly black boxes in their picture.