Image via the Museum of Modern Art. Text from an article in Mental Floss:
The 31-year-old Wyeth modeled the painting's frail-looking brunette after his neighbor in South Cushing, Maine. Anna Christina Olson suffered from a degenerative muscular disorder [Charcot-Marie-Tooth disease] that prevented her from walking. Rather than using a wheelchair, Olson crawled around her home and the surrounding grounds... The sight of Olson picking blueberries while crawling through her fields “like a crab on a New England shore” inspired Wyeth to paint Christina’s World.
Art historians have often snubbed Wyeth's works in their surveys, and some naysayers have attacked the painting's widespread popularity, deriding it as "a mandatory dorm room poster." Meanwhile, critics have chastised Wyeth's attention on Olson's infirmity and characterized it as exploitation. Still others claim there was no art in rendering realistic imagery in paint...
Christina's World remained her favorite to the end. Once when I asked her why, she simply smiled and said, 'You know pink is my favorite color.' 'But you're wearing a flowered pink dress in Miss Olson and holding a kitten. I thought you loved kittens.' 'Course I do, but in the other one Andy put me where he knew I wanted to be. Now that I can't be there anymore, all I do is think of that picture and I'm there.'