require 'RMagick'

class PhotoController < ApplicationController

[...snip...]

    def render_resized_image
                @photo=Photo.find(@params["id"])

                maxw = @params["width"] != nil ? @params["width"].to_i : 90
                maxh = @params["height"] != nil ? @params["height"].to_i : 90
                aspectratio = maxw.to_f / maxh.to_f


                pic = Magick::Image.from_blob(@photo.image)[0]


                picw = pic.columns
                pich = pic.rows
                picratio = picw.to_f / pich.to_f

                if picratio > aspectratio then
                        scaleratio = maxw.to_f / picw
                else
                        scaleratio = maxh.to_f / pich
                end

                #breakpoint

                thumb = pic.resize(scaleratio)

                @response.headers["Content-type"]=@photo.mime
    end
end