Simple gem to let paperclip play nice with thumbnails width, height and size.

Paperclip Meta will get image dimensions right after post_process_styles using paperclips own Geometry.from_file. This should make paperclip-meta storage independent.

Add paperclip-meta to Gemfile:

gem 'paperclip-meta'

Create migration:

class AddMetaToAvatar < ActiveRecord::Migration
  def self.up
    add_column :users, :avatar_meta,    :text
  end

  def self.down
    remove_column :users, :avatar_meta
  end
end

Rebuild all thumbnails to fill meta column if you already have some attachments.

Now you can use meta-magic:

<%= image_tag @user.avatar.url, :size => @user.avatar.image_size %>
<%= image_tag @user.avatar.url(:medium), :size => @user.avatar.image_size(:medium) %>
<%= image_tag @user.avatar.url(:thumb), :size => @user.avatar.image_size(:thumb) %>

Meta column is simple hash:

:style => {
  :width => 100,
  :height => 100,
  :size => 42000
}

This hash will be marshaled and base64 encoded before writing to model attribute.

Meta methods provided:

- width `@user.avatar.width(:thumb)`
- height `@user.avatar.height(:medium)`
- size `@user.avatar.size`

You can pass thumbnail style to all these methods. If style not passed, default_style will be used.

• It will be nice to write some tests. :D