A picture in a new mailer from Rep. Doug LaMalfa's campaign is raising potential legal questions because it appears to be edited to show challenger Audrey Denney signing a pledge to House Minority Leader Nancy Pelosi.

And it isn't the first time District 1 congressional incumbent LaMalfa, R-Richvale, has been in hot water over his office's campaign tactics. Still, defamation experts say there's a lot that would have to be proven for the mailer to be deemed libelous.

The latest mailer shows Denney, a Chico Democrat, signing her name to a pledge to "support Nancy Pelosi and the Liberal Democrats that want to continue our tax increases," the text says.

"Missing the election could be expensive for North State Families," a blurb beneath the picture reads.

Denney's campaign said the original picture shows her signing a pledge not to accept donations from corporate political action committees, something that's been a major talking point for her campaign.

"We think that it’s just symbolic of the fact that we believe we have a compelling vision ... and he doesn't, and so his only option right now is to make up lies about us instead of talking about what he’s doing," Denney campaign manager Brian Solecki said. "Our stance is that, if you don’t have integrity in the small things, how can you expect to have integrity in the big things?"

In an email, LaMalfa campaign spokesman Andre Levesque said that Denney herself "has been running negative attack ads using doctored photos and videos from an OFFICIAL Government Facebook page meant to embarrass Congressman LaMalfa."

"Where was the outrage then? She should look in the mirror," he wrote.

When asked which images or videos Denney's campaign allegedly distorted, Levesque pointed to a video from LaMalfa's website that he says her office downloaded, then "darkened it and slowed it down. That may be illegal."

Levesque went on to say that Denney didn't dispute the content of the mailer, so voters should "consider that as we head into the final weeks."

Solecki said Denney's campaign looked into whether the ads would meet legal requirements for libel, but decided against wading into a court battle.

"We're not going to let this nonsense distract us," Solecki said. "Her integrity and transparency has built the momentum he's so afraid of. He does this so he hopes that it does distract us."

And there are multiple things to consider in proving a libel suit in the first place, defamation attorney Daliah Saper said.

Is the picture obviously a fake, or is it convincing enough that some people would believe it?

"A defense would be that, 'This is obviously not true, anyone would understand that this (picture) was created to make a point,'" Saper said. "And then you would argue, 'That's not true, people aren't that sophisticated.' So context becomes a big part of these defamation cases."

Is the message downright false?

"In campaigns, calling someone a jerk would certainly not be actionable, but stating that the person misappropriated funds or committed fraud, those would certainly be defamatory if they’re absolutely not true," Saper said.

Eric Rose, a partner at Englander, Knabe & Allen, a public affairs firm that handles crisis litigation, said libel allegations over the mailer would be "difficult if not impossible" to prove.

"You have to show where they're damaged," he said. "It's a daily occurrence. The only difference (today) is, it can be done quicker and easier with Photoshop, and you have the advantage of social media, which spreads it quicker than ever before."

Rose pointed out how a judge recently ruled in favor of President Donald Trump after he was sued for defamation by pornography star Stormy Daniels, calling the president's "total con job" accusations against Daniels "protected rhetorical hyperbole."

"The courts just said, 'That's political discourse,'" Rose said.

Still, Saper noted that because there's an image involved, the mailer could potentially face both copyright and "false light" counts on top of libel, if someone were to sue. False light is when a picture is used to convey something that isn't true, she said.

And on the other hand, Rose noted how the mailer could represent an opportunity for Denney's campaign.

"The other side has an opportunity for Election Day to point these things out, show the inconsistencies of the other candidate and let the voters decide," he said.

Stephen D. Solomon, associate director of New York University's Arthur L. Carter Journalism Institute, agreed.

"If a false claim is made, the most effective response for the affected candidate is not a lawsuit but rather immediate ads and statements correcting the record. Done this way, false claims can come back to hurt the election prospects of the person making them," he said in an email.

Denney and LaMalfa face off at the polls on Nov. 6.

His campaign has a history of controversial ads and mailers dating back to 2004.

More:Denney has plenty support in Chico. Does she have enough everywhere else?

Back then, LaMalfa's campaign sent out mailers and also ran radio and television ads linking the then-assemblyman's challenger to pornographer Larry Flynt, whose name is instantly recognizable thanks to the titular 1996 Academy Award-nominated "The People Vs. Larry Flynt."

The ads said challenger Barbara McIver wanted a victory for Flynt, who was funding a PAC that aimed to take down numerous candidates opposed to a bill on gambling — one of whom happened to be LaMalfa.

More:She doesn't have the odds. But could Denney still have a shot against LaMalfa?

McIver said she had no link to Flynt and wouldn't take money from a Los Angeles gaming PAC, but LaMalfa's office at the time stood by the ads, still linking her to the PAC without any evidence.

The campaign also faced a defamation lawsuit until staffer Mark Spannegal publicly apologized for creating a phony website that claimed to represent the congressman's challenger at the time, saying he created it on his own and not as a representative for the campaign.

"Campaigns are getting bolder," Saper said, "about how they present their candidate and what they're willing to do to sway (voters)."

More:UPDATE: District 1 congressional hopeful Denney compares some politicians to tumor she had removed