contact.rb

  accepts_nested_attributes_for :photo


  def image_file=(new_image_file)
    # "image/jpeg; charset=binary" --> jpeg
    server_format = File.mime_type?(new_image_file).match(/^.*\/([^\;]*)/).captures.first.upcase
    set_photo(server_format, :image_file => new_image_file)
  end
  
  def image_file_url=(new_image_file_url)
    return if new_image_file_url.blank?
    
    server_format = Photo.get_server_format(new_image_file_url)
    set_photo(server_format, :image_file_url => new_image_file_url)
  end
  
  def set_photo(server_format, photo_params)
    self.photo.destroy unless self.photo.nil?
    
    public_access = AccessLevel.find_by_name('public')
    photo_album = PhotoAlbum.find_or_create_by_name(:name => 'users', :access_level => public_access)  
  
    photo_params.merge!(:photo_album_id => photo_album.id, 
                        :server_format => server_format, 
                        :name => full_name, 
                        :description => "#{full_name} User photo", 
                        :access_level => public_access)
                        
    self.photo = Photo.create(photo_params)
  end

new_or_edit.html.erb

...

<ul class="photo_upload_form">
	
	<%= content_tag :li, photo_display(@contact.photo) unless @contact.photo.nil? %>
	
	<li>
		<%= f.label :image_file, 'Upload Image:' %>
		<%= f.file_field :image_file,  :class => 'input_object'%>
	</li>

	<li>
		<%= f.label :image_file_url, "or URL:" %>
		<%= f.text_field :image_file_url, :class => 'input_object' %>
	</li>

	
</ul>

photo.rb

  def self.get_server_format(image_filename)
    server_format = image_filename.split(".").last.upcase
    server_format == "JPG" ? "JPEG" : server_format
  end