And potentially a DOS of web-scrapers that download and try and do anything with them, and a DOS of online services that allow users to upload PDF and do someth

And potentially a DOS of web-scrapers that download and try and do anything with them, and a DOS of online services that allow users to upload PDF and do something with them. Does your mail client show a thumbnail preview of PDF docs you receive? Will your mail client get stuck in an endless loop trying to thumbnail a malicious attachment and so on?