Winn-Dixie was played by multiple Picardy Shepherds, a rare breed from France. The DVD extra "Diamond in the Ruff" shows the two principal dogs, Scott and Lyco, but producer Trevor Albert mentions at 18:00 and 40:26 in the DVD feature commentary that, in all, four dogs were used. At 00:36 in AnnaSophia Robb's commentary "Meet Winn-Dixie" she mentions that the stunt dog Tasha jumped over the flour.
To make sure both dogs got on well with AnnaSophia Robb, who played Opal, she was brought in early to get acquainted with the dogs and give them treats. By the time shooting started, they considered her a "safe" area.
Director Wayne Wang wanted to use Picardy Shepherds because he thought they looked similar to the depiction of Winn-Dixie on the book cover and would appear familiar to its readers. Dogs were brought from France when none were available in the U.S. (08:55 in the DVD commentary).
The film, like the book, is set in Naomi, Florida, even though it was filmed in Louisiana. Consequently, the police car and uniform emblems depict the state of Florida rather than the state of Louisiana.
The last name of Opal and her dad, Buloni (mentioned in the dialog at 49:50 in the lunch meat joke), is shown on a sign to the left of the trailer door at 22:37 and elsewhere in the feature. In the scene from 10:45 to 11:03 where Winn-Dixie first arrives at the trailer, only the bottom edge of the sign is visible in the full frame version at 10:53 (when seen on a computer without "overscan" cropping) while in the wide screen version that edge is cropped from view.