Barack Obama, David Cameron and Helle Thorning-Schmidt take selfie at Mandela memorial service

Maybe the candid photo was trying to capture a celebration of peace between nations?

Nearly 100 heads of state gathered in Johannesburg today for the four-hour memorial service for the late South African President Nelson Mandela.

President Barack Obama, British Prime Minister David Cameron and Denmark Prime Minister Helle Thorning-Schmidt sat together. Naturally, it was the perfect opportunity for the powerful trio to grab a quick group photo.

Selfies at funerals aren't looked on highly — there's a tumblr dedicated to mocking the inappropriate shots — nor are selfies taken at memorial services, apparently. A photo of the three leaders grinning for Thorning-Schmidt's camera immediately went viral, drawing criticism for "lack of propriety" from around the world.

"Obama has taken a funeral selfie, so our work here is done," posted the Selfies at Funerals tumblr.

Michelle Obama is also captured in the photo, focused on the sombre occasion and ignoring the selfie action. (Another photo shows FLOTUS giving her husband an unamused side-glare.)

"It could be worse for the first lady, of course: Cameron or Thorning-Schmidt could have asked her to hold the camera," writes Slate's Josh Voorhees.

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President George W. Bush also failed selfie etiquette, posting an Instagram pic of himself with Bono at the memorial.

We learned this lesson last week: A selfish self-portrait faux pas can land you on the front page.

Always think before you pose.