Trusted hardware running remotely-attested trusted software can capture imagery that can be highly assured to be real.
Trusted timestamping, when correctly implemented, completely prevents the generation of imagery after-the-fact. Any false imagery would need to be pre-prepared prior to an event in time, or generated in real time. And a trusted device would need to be exploited to "record" it.
PKI allows individuals/organizations/governments to cryptographically associate their reputation with specific pieces of content.
There will always be the possibility of exploitation of trusted hardware. Apple's eternal fight against the jailbreak scene is evidence of this. However, the combination of these techniques would go a long way towards making the production and distribution of fake imagery difficult.
But, as already stated, the actual problem is societal. People don't really care that much, and enjoy living in their echo chambers.
They allow people generating fake images to sign them so that people believe they are human-generated.
Oh, sorry. I meant "They allow independent sources of truth to do the meticulous work of validating the pedigree of creations, so that with their cryptographically-secured seal you can be confident a human originated the content and a human authenticated it. Only after such work is done would a work be cryptographically signed as authentic."
You know, just like you can always trust the presence of an SSL certificate means a site is who they say they are. /s
