Looming over the southbound lanes of Interstate 35 in Wyoming, Minn., is a grinning portrait of former President George W. Bush, asking “Miss me yet?”

At a time when President Obama’s approval ratings are cratering, the billboard appeared stealthily about a month ago.

“It was put up by a group of small business owners — who want to stay anonymous –because they felt Washington wasn’t listening,” said Mary McNamara, a spokeswoman for the company that owns the billboard. “They felt like it was a good way to get their message out.”

For the past two days, images of the billboard have raged virally across the Internet, with a Google search resulting in more than 100 million hits Tuesday.

The billboard was first reported by Minnesota Public Radio blogger Bob Collins Monday morning.

He took a photo of it while cruising past, about 30 miles north of downtown Minneapolis.

Collins wrote: “It’s beginning to sweep along the Internet, accompanied by various claims that it’s a Photoshop fake. But it’s not. It’s real…

“It’s time to crowdsource this puppy.”

McNamara said company officials were taken aback at the explosion of interest in the billboard, appearing everywhere from USA Today to the Huffington Post.

Told of the millions of hits that have erupted across the Internet, she replied, “oh, my word — that’s amazing. I guess it just shows that billboards work.”

The billboard is standing 13 months after Bush left office, a time when Obama’s popularity has slumped. A Marist College opinion poll published Monday found that just 44 percent of the nation’s registered voters approve of his performance.