if a corrupt image is uploaded using the Image fieldtype, the file is stored and corrupt data is set on the db.

1. save a random text string as myfile.png
2. use PAPIto import it as an ezimage field of an image content, for example with this:
https://github.com/ezsystems/CookbookBundle/blob/master/Command/CreateImageCommand.php

3. image object is created, junk file has been copied into var/storage and db has a row with corrupt data.