[Typo3-dev] deleting (part of) a cache

[Robert John de Stigter]

Hi,
 
I have the following issue. An image on my website contains the username
of a fe_user. This is done in TypoScript with a GIFBUILDER object. The
TEXT object within it has a postUserFunc that returns the username.
These images are cached which is good, but when a user changes his name
the cached images of that user should be removed because the image has
to be rebuild.
 
What is the correct way to do that?
 
Thanks,
Robert