If you don’t know Diana Walker, you certainly know her work. The picture of Hillary Clinton in sunglasses, coolly checking her blackberry aboard a military plane. The tender images of Bill and Hillary Clinton holding hands on a safari in Africa as the Monica Lewinsky scandal raged back in Washington. Even an intimate family shot, when Hillary Clinton appears shocked at the short skirt her daughter Chelsea chose to wear to her father’s second inauguration. Each moment was captured by Walker, the ever-present photographer and 20-year veteran of Time Magazine who covered the Clinton White House, Hillary Clinton’s 2008 presidential campaign and her time as secretary of state. Now as Clinton prepares to launch another presidential bid, Walker published a book of her favorite photographs: “Hillary: The Photographs of Diana Walker.” Over the years, Walker, who is a Clinton supporter, photographed the family in private moments and also at public events like speeches and campaign events. “Every picture has a reason for being in my book,” Walker said in an interview with CNN. “My aim was to show you as much as I saw of a very interesting political figure.” The photograph that brought Walker perhaps the most attention is the instantly-iconic image of then-Secretary of State Clinton thumbing through her blackberry aboard a military plane headed for Tripoli, Libya in 2011. Clinton fans used the image to launch a humorous Tumblr, “Texts from Hillary” that imagined the nation’s chief diplomat corresponding with a number of other high-profile friends such as actress Meryl Streep or Vice President Joe Biden. Walker said she watched Clinton put on her sunglasses before she snapped the shot. “I thought she had been reaching in her bag for her regular glasses, and she put [sunglasses] on and there she was inside this airplane with all of these other people milling around, and she’s totally focused on her blackberry,” Walker said. “And I thought, wow, it’s a strong picture.” Another of Walker’s favorite photographs captures Clinton with a motherly expression of exasperation that many daughters might recognize. Walker’s picture shows Chelsea Clinton opening her winter coat to show her mother the outfit she planned to wear to her father’s second inaugural ceremony. “[Clinton is] on her way and she’s stopped in her tracks when she sees the length of Chelsea’s skirt,” Walker said. “It was one of those kinds of private, funny, delicious moments.” Clinton is expected to launch a second presidential campaign any day now, but Walker will not participate in the day-to-day coverage. She’s leaving that job to a new generation of photographers to memorialize.