Related: Countdown to Election Day 2016: What you need to know today
Newsweek itself responded to the controversy, tweeting that the covers were not produced by them, but by licensee Topix Media.
"For the past six months Newsweek Special Editions has been piecing together a Road to the White House Tribute Issue for both major party candidates," Topix Media CEO and co-founder Tony Romando said Monday.
Romando told CNN Money that Topix decided to print physical copies of the magazine with Clinton on the cover since she is favored to win Tuesday.
Related: Is the fix in? Trump campaign says election is rigged, supporters agree
Romando said if Trump wins, it will rush copies with the Trump cover to the press and Clinton covers will be thrown away.
"Two separate teams have worked to create two special editions tailored to the specific stories surrounding each candidate," he sad.
"Unlike hard news magazines, commemorative editions for sporting events, elections and unfortunately deaths are created weeks, months, and even years in advance," Romando said. "The largest publishers in America have dozens of tributes ready to print at plants across the country."
This is no different than T-shirts being printed in advance bearing the names of both competing sports teams ahead of a championship game, Romano explained.
"One minute after the Chicago Cubs won the World Series their commemorative T-shirts went on sale and the losing team's T-shirts were scrapped," Romano said. "As is customary in the collectible consumer goods community. This was a business decision. Not a political decision."
CNN Money reported that the woman who tweeted the photo deleted her Twitter account, and if she is a bookseller like she claimed, she may be out of a job for releasing an image of the magazine before it's scheduled to be on sale.