paperclip, authlogic and callback issue

I use authlogic for authentication and paperclip for handling user's
profile picture attachments.

I use the following method to get the current_user

    def current_user_session
        return @current_user_session if defined?
(@current_user_session)
        @current_user_session = UserSession.find
    end

def current_user
        return @current_user if defined?(@current_user)
        @current_user = current_user_session &&
current_user_session.record
    end

and the following after_save callback to regenerate the profile image
if the image has changed.

   after_save do |user|
        if user.image_changed?
            Delayed::Job.enqueue ImageJob.new(user.id)
        end
    end

The current_user method issues a UserSession.find call and
Looking at the docs it seems UserSession.tries to Log the user
in, which results in an update to certain fields (updated_at, token
etc. but not the profile image), which results in a
save of the user record, which in my case results in after_save
callbacks firing. This after save callback checks to see if there has
been a change to user's profile image, which unnecessarily consumes
time.

Now this is fine if the user indeed is trying to
update profile, but since I use current_user in many different places
within my app, this callback is getting fired (and its an expensive
call), for no reason.

I understand this isn't exactly authlogic issue, but is there anyway I
can avoid this, i.e. either not update the user record or somehow
differentiate between what is a profile update and what is an update
resulting from this UserSession.find login?

Thanks

Just speculating, but what if we rephrase the problem: the User
after_save callbacks are expensive.
Would it be possible to move whatever attributes the callbacks modify
to another model?

your User.rb after_save callbacks to another model?