Spatial spam might be multiple media: text and graphics popups, photographs, and probably video and sounds too. So geocoded jpegs are only a part of a larger problem.
I think your ideas are very good for authenticating photographs for professional applications, like photo surveying, and field scientific photography.Perhaps someone like Ricoh would work with you on this. Have you seen the very professional Ricoh caplio g3 gps camera?
Widespread web applications of this approach for spam prevention might take quite a long time becuase of the problems of scale: It will only work if a lot of communities on the web can be convinced to work in alignment, multiple hardware companies, client software builders, service architects, etc.
>Do you think there is a trivial way of bypassing the GeoSpatial Spam Prevention Method mentioned here?
Yes. There's nothing to prevent spammers from driving down a road, taking continuous location authenticed images of an ad graphic. the location is authentic, but it's still spam
>Do you think the cost involved would be too high? If so what according to you would be the most expensive aspect of the system? Justfy.
Cost of standards negotiation would be high, and long time consuming with other hardware, software, and web services developers and standards groups. Hardware and software engineering is probably straight forward to implement. Service architectures are dificult:How will I search for photos by location if I have to authenticate to parse the location
>Do you think there are easier ways of accomplishing the same or better results? if so what are they?
what about embedding the private key in the gps, instead of the camera, for,more gerneral use beyond jpegs, and mpegs, and other sensors?