Can Receive jpeg but can`t send

[Rafael Andrade]

Hello Members,

I would like to know if there is a method so I can have the following 
configuration on my MTA:

The user foobar can receive attached jpeg files, but cannot send 
attached jpegs.  I need this because some employees must receive some 
files in a specific extension, but cannot send files in that same 
extension.

Thanks in advance

Rafael