Late Thursday night, state Sen. Branden Petersen tweeted:

The issue? The discovery, by BuzzFeed, that Republican U.S. senate candidate Mike McFadden's website included a background image of a (gasp!) Canadian bay.

McFadden spokesman Tom Erickson told the Star Tribune on Friday morning that the image was quickly replaced with a photo of a Minnesota lake.

"We are not a typical campaign and we are willing to admit we made a mistake. We just wish Al Franken would admit that he made a mistake in voting for a health care law that kicked 140,000 Minnesotans off their health care plans," Erickson said.

But the Republican hopeful is not the only politician with potential stock photo issues.

McFadden's Republican rival Julianne Ortman has a wedding ring photo on a campaign brochure next to her fact check refuting what the campaign says was another candidate's implication that "Julianne doesn't support traditional marriage:"

The brochure says that Ortman has "voted 15 times in favor of the Marriage Amendment and never voted against it. She also voted "No" on the same-sex marriage bill."

But the wedding rings, being of the same thickness and size, look an awful lot like two male wedding rings. So much so that backers of same-sex marriage frequently use the stock image on their websites, as do news outlets when illustrating articles about same-sex marriage.

Jim Sanborn, Ortman's political director, said: "matching wedding rings are appropriate for any wedding." He said that his parents have worn matching rings for their 50 year marriage, although he did note that his mother's is a bit smaller.

As social media was dusting up over the McFadden Minnesota lake vs. Canadian bay issue, a Republican activist noted that Democratic U.S. Sen. Al Franken, whom Ortman and McFadden hope to defeat, has a photo on his official website that looked very unlike a Minnesota courtroom.

That stock courtroom image is used by law firms across the country.

Ed Shelleby, Franken's communications director in Franken's senate office, acknowledged that the website uses stock photos and that the courtroom on the website is a stock photo.

On his campaign side, Franken has also acknowledged -- even joked about -- stock photos in a fundraising email.

"You've seen us shaking hands in business suits, posing together on college campuses, and laughing while we eat salads. You've seen us on billboards, in magazines, and on pretty much every political website. We are the people in stock photos," said an email two years ago.