Can't make to output images in GPTs

Hi, I have a question related with GPTs.

In GPTs, I uploaded a .zip file with 30 image files and configure it to output images based on the user’s needs.

Previously, the image output was working fine, (I had written a prompt to use subplot function to show the image)
But now, I am having a problem that only the code (generated by the Code Interpreter) is output, not the image.

I was wondering if anyone else is having the same problem.
I think that this problem is appeared after GPT-4o release…

Thank you.