OTTAWA -- Andrew Caddell fully expected that a picture of an abandoned, broken-down bus Photoshopped to include Stephen Harper's image and election campaign slogan could go viral.

But the Foreign Affairs senior policy adviser admitted Thursday he was a bit surprised to see the photo, recycled on his Facebook and Twitter accounts from Frank magazine, get shared more than 12,000 times in two days.

"I guess it's a pictorial commentary on a very interesting election campaign," Caddell said in an interview.

"It's a great source of entertainment, especially when things are bad in this world."

The photo of the decrepit, wheel-less bus, apparently originating in Mongolia and touched up with Conservative party signage on its side, was just one example of how the federal campaign was playing Thursday on social media.

Indeed, the past social media antics of candidates and officials haven't all been in fun for any of the three main parties in recent days.

Tweets belonging to Alberta Liberal hopeful Christopher Brown from 2009 surfaced Wednesday in which he uses profanity and insults women with a derogatory term.

On Thursday, Liberal Leader Justin Trudeau said Brown, running in Peace River-Westlock, had been dealing with difficult circumstances at the time, adding that he intended to speak with him later in the day.

Not long afterward, Brown issued an apology, saying that he had sent the tweets after losing his partner in a car accident involving a drunk driver.

The Liberals were also distancing themselves from Vancouver-area candidate Joy Davies for comments she made on Facebook suggesting that marijuana decreases domestic violence and causes no harm to children.

Trudeau said Davies views were not his own and that she didn't speak for the party.

The Liberals have already lost one candidate in Alberta over old Twitter posts that caused controversy.

The Tories also dumped two candidates over old social media posts and videos, while a communications adviser to NDP Leader Tom Mulcair apologized this week for two-year-old posts he made about the Catholic church's stance on homosexuality.