> But lets say I am a reputable account posting a (faked) photo of you and Marty doing something illegal, how does nostr help you challenge the veracity of that photo?

YOU CANNOT CRYPTOGRAPHICALLY PROVE SOME THING DOES NOT EXIST, ONLY THAT SOME THING EXISTS.

IT DOES NOT MITIGATE THAT UNLESS THE PHOTO IS A MODIFIED VERSION OF AN ALREADY EXISTING PHOTO THAT WAS HASHED AND SIGNED. 

 Agree. 

But there is an indirect protection. To further your point of the «open source social score», I risk my reputable account by spreading false content. Might work well for my engagement until it doesn’t. 

 VERY TRUE.

AND IF YOU POST FAKE SHIT RELAYS WILL KEEP RECORDS OF THAT AND WE CAN VERIFIABLY PROVE YOU POSTED FAKE SHIT IN THE PAST.

LOTS OF FAKE NEWS ACCOUNTS DELETE POSTS AFTER THE FACT. NOSTR FIXES THAT. 

 this is why NOSTR is so necessary in the times we are living!