Chen Zhi understood her mother's thoughts and knew she was worried that Si Xi would be unhappy. Because her presence in the photos slightly felt like she was taking the place of Si Xi's own mother.
Fortunately, Si Ye wasn't bothered by these things, but it was only natural for Si Xi to care.
However, Mom should have taken one with them. Not in any specific role, but as a mother—in her role as Si Ye's mother-in-law, she should have taken a photo with them.
After Chen Zhi explained her reasoning, her mother thought about it and nodded in agreement. But she also made it clear to Si Chengye that she would only stand next to Xiaozhi tomorrow, not with him.
Si Chengye knew this was her biggest concession, so he agreed to her request.
The next day, no one knew how Si Ye managed to invite Si Xi and Song Jiamei over, but eventually, everyone stood together for a family portrait.