I believe the whiteflash is retina overload. It would cast a shadow on the picture too. You would get the logo or text watermarked on the persons photos. You would probably get lots of red-eye in the photo. but the anti- red eye flashes use repeated short bursts to prevent the redeye effect.
I suppose you would either need to turn off the anti-red eye feature, or put a lcd shutter infront of the flash to display the image, on one of the non-photo image bursts. I would expect thought he longest flash would the one for the photo. Aside from that, it is intentionally blinding, and people would be getting into accidents after being exposed. I have read that Non Lethal weapons tech sometimes uses strobes to dazzle a intruder. It would be probably viewed by the courts as being a form of Assault. and have criminal charges involved. Wow, another brain cramp from on high.
@Wize, @geness: I had the exact same thought. That idea would definitely work as long as you used a simple corporate logo that is sufficiently recognizable. For example, most consumers don't need to actually read the word "Ford" to recognize a Ford logoâ€”simply catching a glimpse of an oval with the script lettering inside of it is sufficient; other corporate logos, such as Coca-Cola's, Pepsi's, Microsoft Windows', and even the "Intel Inside" logo are designed similarly, so that consumers will recognize them without needing even to look directly at them. If you superimpoased one of these logos onto the flash bulb, the person would indeed be seeing that highly recognizable logo for several seconds. It would be a highly effective, if sinister, means of subliminal advertising.
That would only give you small letters. You need big letters. If they were looking at the camera lens, the flash will be off centre and you can't really turn your eyes to read the burned image.