This post was originally published on the New Bamboo blog, before New Bamboo joined thoughtbot in London. There are some fantastic gems and plugins out there for handling images in Rails apps, such as Paperclip, Attachment-fu, etc., that on the whole are well-written and do a pretty good job. However, something has always narked me when using them. In general, to add a preview_image to, say, your
![On-the-fly image handling with Dragonfly](https://cdn-ak-scissors.b.st-hatena.com/image/square/beac31a4be8e4962e2fefc94fd70b667eb3e9cec/height=288;version=1;width=512/https%3A%2F%2Fimages.thoughtbot.com%2Fblog-images%2Fsocial-share-default.png)