About the incompatibility between the screen size and the characters

I am a beginner. I tried to generate a 9:16 picture in the gpt4 interface, but it always looks like the following picture. I want to know why? I set this up in “Customize ChatGPT”: Make sure to use accurate prompts to describe the people I’m mentioning, and always produce two images. The content must be displayed vertically and the image ratio is 9:16. But still The inability to change characters is a lateral problem that really bothers me. please help me.