Strange attachment_fu problem: thumbnails limited to 1

Hi, I am encountering a strange issue with attachment_du: whatever classes of thumbnails I define, only one is recognized and accordingly processed when creating a new image.

For example: :thumbnails => {:thumb => "65x65", :big => "548x548"} just produces a "big" thumbnail and the "thumb" thumbnail simply doesn't exist. But even more strange, when I change the order of the thumbs declaration in the thumbnails hash it still produces just the "big" thumbnail. Changing the thumbnail class names or size declarations doesn't have any influence.

Anyone has a clue what might be wrong here?

Here is the attachment_fu relevnat model code: class Pic < ActiveRecord::Base has_attachment :content_type => :image,                   :size => 0.kilobytes..50.megabytes,       :storage => :file_system,       :path_prefix =>'/public/photos',       :thumbnails => { :thumb => "65x65", :big => "548x548" }

  validates_as_attachment

end