It's a sad day to be an Instagram co-founder. You see, Facebook offered to buy Snapchat for $3 billion this week (an offer that Snapchat declined). Back in 2012, Facebook bought Instagram for a paltry $1 billion. Mistake, losers! As Business Insider trumpets, "Industry People Are Whispering That Kevin Systrom Blew It Selling Instagram For $1 Billion."

According to people in the know, Instagram is worth a lot more now — maybe even $15 billion. Town Pauper Kevin Systrom, who's net worth is estimated to be $400 million, could be richer if he had waited until today to sell. But he didn't, and for that, he will likely end up living under a bridge somewhere in the Bay area.

BI notes that "activist-investor" Eric Jackson thinks Systrom messed up: he "has to be feeling like he totally missed this wave. Instagram likely worth $15B today minimum." Startup investor Shervin Pishevar really piles on: Instagram was an "insanely smart, cheap acquisition by Zuck." Yep, Facebook founder Mark Zuckerberg really got a Costco deal on that photo-sharing app.

Systrom has yet to comment on his real dumb move of becoming a multi-millionaire at age 28