base64_image_wrapper.rb

class Base64ImageWrapper < StringIO

  def initialize(data, name=nil)
    @name = name || 'image'
    @blob = Base64.decode64(data)
    super @blob
  end

  def original_filename
    "#@name.#{content_type.split('/').last}"
  end

  def content_type
    @content_type ||= Magick::Image.from_blob(@blob)[0].mime_type
  end
end