A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Based on my research, the Designer Editor integration in PowerPoint does not include a supported setting that allows users to disable it. From my understanding, this AI-powered image editing feature is built into PowerPoint and currently cannot be turned off independently.
You can refer more via this link.
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If you would like this functionality to be configurable in the future, you may consider submitting feedback directly from the PowerPoint application (Help > Feedback). This feedback may be reviewed by the PowerPoint product team and could help influence future product enhancements and feature improvements.
I hope this information helps address your concern.