The biggest mystery among the 50 photos in the CEPA Gallery exhibit Thursday evening in the Market Arcade was the shot of a bison sculpture lurking behind a stand of purple flowers.

Everyone who saw it wondered the same thing: “Where is that?”

There’s no title, only the name of the photographer, Mark C. Poloncarz.

The county executive is one of the 50 notable Buffalonians who were handed disposable cameras loaded with color film a few months ago and instructed to go out and take creative photos.

“How big do you think that buffalo is?” Poloncarz asked when he was buttonholed downstairs at the arcade on Main Street.

“It’s about this high, 3 feet off the ground," he said. “It’s in McClennan Circle at McKinley and Red Jacket parkways in South Buffalo. The flowers had just bloomed. We drove by on the way back from an event. I just pulled the car over and gave it a shot.”

Poloncarz isn’t the only public official with a photo in the Visions of Greater Buffalo exhibit. Delaware Council Member Michael J. LoCurto captured the colorful sunburst stained-glass ceiling in the Common Council Chambers in City Hall.

“I wanted to do places that were iconic, but also related to my job,” he said. “I took pictures in the park, on Elmwood Avenue. They say there were 27 shots in the camera, but I think I took 32.”

“I thought the film was black-and-white, so I was looking for shadows and light,” said Cathleen Calleri, who runs education programs for health care workers for SEIU Local 1199 and who caught the Nancy Rubins canoe sculpture in front of the Albright-Knox Art Gallery from an unusual angle. “People were probably asking, ‘What’s that crazy woman doing under there?’”

After the 50 cameras were returned, the film was professionally developed and a panel of judges picked one photo from each.

Each photo has an auction ticket hanging below it, with the money going to support CEPA’s many educational and visual art programs. Minimum bid – $75. Additional bids are in $25 increments.

Garnering a $100 bid by mid-evening was a much-admired image of sea grass with silvery water and breakwaters in the background. Tifft Farm?

No, said the photographer, Assemblyman Sean Ryan. It’s in front of the West Side Rowing Club.

Ryan and his wife, attorney Catherine Creighton, comprise one of two couples in the exhibit. The other is Ellen Goldstein, community relations director for the Jewish Federation of Greater Buffalo, and her husband, advertising executive Mitch Flynn, who’s one of the originators of the annual Ride for Roswell. Flynn’s photo is of the long shadow of a bicyclist.

Gallery and event chairwoman Nancy J. Parisi explained that this current Visions project is a little different from the previous one she headed in 2010.

The reception was Thursday night, not on the weekend. It was in the fall instead of the spring. It included a basket auction and a $5 photo booth. And it continues Public Visions, started last time, when the public at large was invited to submit iconic photos taken with their smartphones. The best of them stream on a video screen in one of the galleries, sharing the space with framed iPhone photos by former photojournalist Cathaleen Curtiss, now director of entrepreneurship studies at Daemen College.

One who went to great pains was Linda Pellegrino, host of Channel 7’s “AM/Buffalo” talk show, whose photo of boats on a placid Hoyt Lake in Delaware Park is featured on the Visions brochure.

“I tried to make it timeless,” she said. “There are no telephone lines, no cars. But you don’t know if you’ve taken a good picture. You wonder, did I jiggle the camera?”