PF moderators have no way of knowing how careful even a long-time poster is regarding computer security! I for one strongly urge PF to continue to insist on individually moderating images and other attachments, including scanning them for possible malware. This is very important!
Please recall that many popular "social networking" websites, including MySpace, LinkedIn, Facebook, Friendster, and Wikipedia, have experienced problems with phishers uploading dangerous malware which seriously affected at least some visitors. To mention only one item from a long long list of possible unintended consequences of the proposed change.
Decisions which affect security always involve a tradeoff between convenience, practicality, and security. IMO, security should remain a primary consideration for the maintainers of PF, particularly given evidence of the changing nature of criminal activity on the web which seems to indicate a trend toward targeting social networking sites.
(Since this discussion affords me a rare chance to say something nice about WP, I note that one reason why so few security problems with WP, e.g. compromise of non-public portions of the internal database, have hit the news is that Brion Vibber has been much careful about security than some other networking website admins have been. Another reason, less happy, is that even computer literature commentators generally seem to be badly confused by the complexity of WP's social and software structure.)
If PF should seriously consider changing its policy by allowing users to upload anything which could cause unprotected browsers to execute unexamined code, please announce the change well in advance and give concerned users the option of not only not revisiting PF, but of having their information wiped from the internal database before the change is implemented!