The entropy check is the user's eyeballs.
The camera data is displayed on screen. There's even a final photo presentation that waits for the user's "accept/retry" review.
Image entropy is orders of magnitude more entropy than dice.
480x480 pixels * 24 bits per pixel.
Even if the sensor isn't capable of reproducing every possible color value, heck, even if it just produced black and white threshold (on/off) pixels, you'd still have 480x480 = 230,400 bits of data.
AND up to 50 of the live preview frames at 240x240 are chain hashed in.
It's insane overkill.
