DALLAS — Chris Wunder, who has spent the better part of the last four decades photographing schoolchildren or managing those who do, used to tell kids they could bring a “personal prop” for spring portrait day. When he forgot to qualify the invitation, some, especially in rural areas, would arrive with shotguns, venomous snakes and, once, even a pony.Other dangers were self-abetted. He no longer provides hair spray, after a young mischief maker in North Carolina used a lighter to turn the canister into a flamethrower.Mr. Wunder’s toughest battles, however, haven’t been getting youngsters to stand still and smile, or getting their parents to fork over $27 for three portraits and a few wallet-size photos, but with Lifetouch, the school picture behemoth that photographs roughly half of America’s 50 million schoolchildren every fall. The company is based in Eden Prairie, Minn., though, if you ask Mr. Wunder, there is little Edenic about its business practices. In his early days as a manager at Inter-State, the country’s second largest photo company, Mr. Wunder watched as Lifetouch gobbled up competitors and grew to $1 billion in annual revenue. Now, as the owner of the photo franchise PortraitEFX, he has lost contracts to Lifetouch salesmen with fat expense accounts.Last year, Shutterfly, the online photo printing giant, acquired Lifetouch for $825 million, unlocking even cheaper production costs and a more seamless online sales machine. The “dark side,” as Mr. Wunder calls Lifetouch, is set to expand its empire.But there is a resistance, and Chris Wunder is its leader.And so, on a Monday morning in March, the first day of the #1 Original School & Sports Photography Boot Camp, at a Dallas airport hotel surrounded in all directions by chain restaurants and strip clubs, Mr. Wunder strutted before a projector screen. He barked advice to three dozen independent school photographers, a mix of veterans and newbies, all of them looking for big paydays.Victor Rosas, 45, of Amarillo, Tex., is trying to make the transition from shooting weddings and quinceañeras that can last 12 hours. Casey Craig, 33, from Conroe, Tex., quit her job at an engineering firm during an energy downturn to shoot full time. Michael Feldman, 62, joined his father’s photo business 15 years ago, but with two new high school contracts this fall with 4,000 students, he wants a tuneup. They’ve paid up to $300 each to be here.Over the next five days, Mr. Wunder, 65, would teach them how to beat not only Lifetouch, but also such regional powers as Strawbridge Studios and Barksdale School Portraits. He would flip PowerPoint slides like “You NEED to earn a good $IX-FIGURE income” and “Fundamentals of Posing-Head Tilt.” He would confide the secret to defeating head lice when 100 kids use the same mortarboard: Buy lots of coffee filters and call them “hygienic cap liners.” And he would stress the importance of reading obituaries in the local newspaper.“The industry rule is you do three days of