Typo3 CKEditor image from FAL

问题

I set up a fresh TYPO3 8.7.4 installation with CKEditor and rte_ckeditor_image to get images from FAL.

In the documentation from rte_ckeditor_image it says:

The maximum dimensions relate to the configuration for magic images which have to be set in Page TSConfig:
# Page TSConfig
RTE.default.buttons.image.options.magic {
    maxWidth = 1020  # Default: 300
    maxHeight = 800  # Default: 1000
}

I did this, but still I can't make the width of an image bigger than 300px.

I looked at the source code from TYPO3 already. There is a file typo3/sysext/core/Classes/Resource/Service/MagicImageService.phpwhich got two variables: $magicImageMaximumWidth and $magicImageMaximumHeight. If change the value of them, I can make the width of an image bigger then 300px.

The file got also a function setMagicImageMaximumDimensions(array $rteConfiguration) which should change thoose two variables but seems like it doesn't do so.

Did I do something wrong or is it impossible to change the maximumg image dimensions?

Thanks.