Paperclip is nice but its not working on the update action.
Well, to be exact, I can attach new picture records via a scaffolded controller and edit them, but the edit controller loses them when the record is updated?
Is this a known issue?
Remember to attach :html => { :multipart => true } to your form_for declaration for both the new.html.erb and edit.html/erb
I have
form_for (@user, :html => {:multipart => true}) do |f|
and paperclip not working.
I noticed:
Parameters: {"user"=>{"profile_pic"=>#<File:/tmp/CGI.1316.5>
It seems to be uploading to /tmp, but it doesn't get copied over to RAILS_ROOT/public/profile_pic like I'm expecting it to.
Does anybody know what might be wrong?
BTW, I'm using Rails 2.1.0 with paperclip from the github repository.
David 
I am having the exact same issue as well.
At first I thought it was something with my Amazon S3 setup, so I removed all the S3 stuff and tried it with the file system settings and I'm having the same result. No errors are thrown by paperclip but its just not working.
The file does appear to be getting submitted via the form:
"avatar"=>#<File:/var/folders/qU/qUtWQXmZFhincA4TKuqR4++++TI/-Tmp-/CGI. 13460.11>,
but nothing happens afterwards and I cant access it via model.avatar.url, etc...
btw, I'm on Rails 2.1.1
I figured it out.
Stupid, but I forgot to add :avatar to the list of attributes. So it was protected from mass_assignment.