How to save processed RMagick image using Paperclip without writing to file

I am trying to load a file (RMagick processing output) into s3 using paperclip. I keep getting the error

No handler found http://upload.wikimedia.org/wikipedia/commons/thumb/4/48/EBay_logo.png/800px-EBay_logo.png= > 800px-EBay_logo.png PNG 800x349 800x349 + 0 + 0 DirectClass 8-bit 37kb

Basically on my system - the user uploads the logo using an external url, I process the logo and trim the spaces and upload it to my s3 system. I am using a temp file as an average person, but I want to do this directly:

In my model, I do this:

  def fetch_and_trim_logo
    puts "logo is #{logo}"
        if logo_changed?
         response = RestClient.get logo
         if  response.code == 200
            img = Magick::Image::read(logo)[0]
            puts "This image is #{img.columns}x#{img.rows} pixels"
            trimmed_img = img.trim
            puts "Trimmed image is #{trimmed_img.columns}x#{trimmed_img.rows} pixels"
            temp_file = Tempfile.new(["trimmed_image",".png"])
            trimmed_img.write("png:" + temp_file.path)
            my_asset = visitor.user.my_assets.new
            my_asset.uploaded_file = temp_file
            my_asset.save
         end
        end
  end

      

        
        
        
      

    

My My_asset Model has all the paperclip settings, for example:

Class MyAsset<ActiveRecord::Base
---
---

has_attached_file :uploaded_file

  attr_accessible :uploaded_file
  validates_attachment_size :uploaded_file, :less_than=>5.megabyte
  has_attached_file :picture,
    :styles => { :thumb => "300x300#" },
    :default_url => "//#{ENV['CLOUDFRONT_URL']}/assets/picture_missing.png"
end

      

        
        
        
      

    

This method works! but when i change

    my_asset = visitor.user.my_assets.new
    my_asset.uploaded_file = temp_file 
    my_asset.save

      

        
        
        
      

    

to

    my_asset = visitor.user.my_assets.new
    my_asset.uploaded_file = trimmed_img
    my_asset.save

      

        
        
        
      

    

where trimmed_img is the result of RMagick processing, I get the error "No Handler found"

any ideas how to fix this?