Continuity mistake: In the scene where Shelby is getting her hair done before her wedding, she begins to have a diabetic attack. Sally Field lifts up the hair dryer she is under...then in the next shot, you can see her lift it again.
Continuity mistake: The Christmas decorations in the outside of the house change as to where they are and what they are.
Continuity mistake: Janice van Meter's dress at beginning of the reception is floral with a flowing bottom. Then when when dancing with Trudy's son and looks like "2 pigs fighting" its tight and cream.
Continuity mistake: In the wedding reception dance scene, you see a couple dancing amongst the guests on the dance floor. The female is wearing a seafoam green dress with a large matching bow in her hair. About 2/3 of the way through the song "On the Bayou," you see this same couple run onto the dance floor from off camera to watch the featured dance couple, as if they had never been on the dance floor at all.
Continuity mistake: When M'Lynn and Truvy are sitting in the backyard drinking tea after the funeral, there is no greenery next to where Truvy is sitting. In the next shot, when Clairee and Ouiser walk in the backyard together next to Truvy, there are now bushes and some trees that weren't present in the shot beforehand.
Continuity mistake: In the scene after Shelby's funeral has taken Place where M'Lynn, Truvy and baby Jackson are in the backyard, Annelle is bringing the two ladies some tea. In the next shot, Ouiser and Clairee walk into the backyard and now present in the shot next to Truvy is a small tree and shrubbery that was not there before.
Answer: I believe it is because the child playing Jack Jr. was basically crying through this whole scene, as you can see. It's most likely his (actually her, as the real baby was a girl) real mother holding him to calm him down. Also, when the family is saying "Blow, blow," you can hear a female voice that is neither Julia Roberts or Sally Field.
When she is sitting with Jack Jr, it is before she goes to get her hair cut. When she tells M'Lynn she wants to cut her hair, she is wearing it in a banana clip and you can see the hair past her shoulders. When "she's" sitting with Jack Jr, there's no hair to be seen. Total stand in.
Daniel Camp is the actor who played Jack Jr.
Along with Daniel two other children played Jack Jr, C. Houser and Clara Gabrielle.