rails4 carrierwave + S3 adding new image version
<p>I have a rails4 app, profile images are uploaded with carrierwave and served by S3. </p>

<p>I used to have one image version (<code>base_thumb</code>) for resizing. Now I'm trying to add <code>user_thumb</code>, but if I change the code from <code>profile.avatar.url(:base_thumb)</code> to <code>profile.avatar.url(:user_thumb)</code> then the image is not displayed to users who created profile earlier since that image version is not on S3.</p>

<p>How can I solve this issue?</p>

<pre><code>version :base_thumb do
  process :resize_to_fit =&gt; [85, 85]
end

version :user_thumb do
  process :resize_to_fit =&gt; [40, 40]
end
</code></pre>