dgorodnichybak/paperclip_example

1. rails new SliceAutomation

2. add gem to Gemfile => gem 'paperclip'

3. bundle install

4. rails g scaffold screenshot title:string

5. rake db:migrate

6. rails generate paperclip screenshot picture
   screenshot [model]
picture [field]

7. rake db:migrate

8. In Model:

    class Screenshot < ActiveRecord::Base
        attr_accessible :title, :picture
        has_attached_file :picture, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "/images/:style/missing.png"
    end
   

9. In Views:

    <%= form_for @screenshot, :url => screenshots_path, :html => { :multipart => true } do |f| %>
        <%= f.file_field :picture %>
    <% end %>
   
    <%= image_tag @user.avatar.url %>
    <%= image_tag @user.avatar.url(:medium) %>
    <%= image_tag @user.avatar.url(:thumb) %>
   

=============

http://rubydoc.info/gems/paperclip/3.4.1/frames