(WRCB) -- A holiday picture posted on Randi Zuckerberg's Facebook page was shared with thousands of people, prompting the Facebook CEO's sister to start a Twitter feud with the poster.

Randi Zuckerberg, was the former head of marketing for Facebook is now the executive producer of a reality television, 'Silicon Valley' posted a photo on Facebook.

The candid family picture is of Randi and her family (including sister Arielle Zuckerberg and Facebook CEO Mark Zuckerberg) reacting to the new Facebook Poke app.

The issue arose when Callie Schweitzer, director of marketing and projects at VoxMedia, saw the photo on Facebook, and posted it publicly on Twitter.

That's when the social media war of words began.

"@cschweitz not sure where you got this photo. I posted it on FB. You reposting it to Twitter is way uncool," Zuckerberg posted in a tweet to Schweitzer.

"@randizuckerberg I'm just your subscriber and this was top of my newsfeed. Genuinely sorry but it came up in my feed and seemed public," said Schweitzer.

Facebook's complex privacy settings have created headaches for many users as they try to sort out their own answers, but the irony of the moment was not lost on those watching the event from the sidelines.

The offending photo post was deleted, but not before the world read about the digital spat.

"Digital etiquette: always ask permission before posting a friend's photo publicly. It's not about privacy settings, it's about human decency," Randi Zukerberg later tweeted.