actiontext/app/views/action_text/attachables/_remote_image.html.erb
<figure class="attachment attachment--preview">
<%= image_tag(remote_image.url, width: remote_image.width, height: remote_image.height) %>
<% if caption = remote_image.try(:caption) %>
<figcaption class="attachment__caption">
<%= caption %>
</figcaption>
<% end %>
</figure>