Images under 1MB are not being compressed

Hi all

Images that are above 1MB get automatically compressed on upload.
Images that are smaller than 1MB are added to the database in their raw form.

So, if someone uploaded a 900 KB image, the post will display a 900 KB image.

On this website, all content is user generated.
Both posts and comments have many images.
They have to be automatically compressed by WordPress on upload.

Please, tell me how to change this setting so that all image sizes are compressed.