I want to stop generate thumbnail, how can I do

I want to stop generate the thumbnail, how can I do
I can’t find any option in the document
what should I do by editing extensions/upload/config/setting.json

thank you very much

  • Settings
    • Media Library

then turn of responsive and or size optimization

I already turn off the responsive and size optimization
But still upload the thumbnail automatically (only large, medium…etc disappear)
And I still can’t find any place to turn of thumbnailQQ

thanks