there is the file deny pattern which denys upload of certain files see the documentation:

https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/Configuration/Typo3ConfVars/BE.html#confval-globals-typo3-conf-vars-be-filedenypattern

the image processing settings you found are tell typo3 which files are "images" which cann be processed by the installed image processor (graphicMagic/ImageMagic) as this might be different depending on the version or installed libaries. so somoe system might be able to generate images from pdf files and other don't or similar