I am using omniauth-facebook and trying to get the profile picture to show up using paperclip. Here is the code I use to get the picture to my User model 

```
def picture_from_url(url)
    self.profile_pic =open(url)
end

```

However, it always saves as stringio.txt. So searching on this behavior I found out that paperclip allows for callbacks so I wrote the following method in the User model to rename the filename 

```
def rename_profile_pic
    self.profile_pic.instance_write :filename, "#{self.username}.jpg"
end 

```

and passed it to the callback 

```
before_post_process :rename_profile_pic

```

But this doesn't seem to help.

Any ideas how i can fix this ? 

thanks