Regenerate Thumbnails Plugin Passes 5 Million Downloads, Rewrite in the Works

Regenerate Thumbnails, written by prolific plugin developer Alex Mills, has passed 5 million downloads. The plugin was first released nearly a decade ago in August 2008 during the days of WordPress 2.6. Regenerate Thumbnails is used to retroactively generate new thumbnail sizes for past uploads. It has become an indispensable utility over the years, helping millions of users successfully transition between WordPress themes that have different featured image sizes.

Regenerate Thumbnails version 1.0.0

“I was freelancing at the time and according to an ancient post on my blog, I apparently wrote it as a client needed the functionality,” Mills said. “I don’t remember that though and I certainly never figured it’d be installed and activated on over a million sites like it is today!”

Regenerate Thumbnails is downloaded thousands of times every day, and, fortunately, it is the type of plugin that doesn’t generate too many support issues. Mills said he is thankful for the many volunteers on the WordPress.org support forums who have also helped manage the load. Despite the continued and widespread use of the plugin, Mills has never considered cashing in on it.

“I’d never monetize any of my plugins,” he said. “I write them for fun not profit. It would be a conflict of interest anyway due to my employment at Automattic.”

Regenerate Thumbnails is a fairly straightforward plugin that rarely requires updating, but this year Mills said he has tried to give it a lot more love and will soon be releasing a complete rewrite.

“The rewrite is currently taking place on GitHub and is a complete rethink of the plugin, both in terms of the interface and underlying technologies,” Mills said. “The interface is powered by Vue.js, which I’m learning and using for the first time, and the WordPress REST API. I also have a full suite of unit tests for PHPUnit to verify that the plugin code is working as intended, both now and into the future. Those have been incredibly useful while writing the plugin and I highly recommend other plugin authors make use of them too. WP-CLI makes it very easy to set up.”

After nine years of supporting Regenerate Thumbnails, and many other plugins, Mills said he doesn’t consider himself the best example when it comes to maintaining plugins. His advice to other developers is “try to make sure to write your plugins to be future-proof.”

“Outside of some updates last month, the last real changes to the plugin were made in 2012!” Mills said. “I wrote the plugin well the first time around and it’s just worked mostly fine ever since because it uses built-in WordPress code to do the work.”

This is the reason why Regenerate Thumbnails has already blazed past its major milestone at 5,762,713 downloads and is well on its way to 6 million before the end of the year. Users still find the plugin to work as reliably as it did in 2008.

Mills said that making a plugin future proof is key if you write code all day for a living and then find it difficult to write more in the evenings and weekends for WordPress.org plugins. However, due to his current illness, he hasn’t worked in nearly a year since October 2016.

“While I’m still battling the leukemia, I’m at least feeling better than I was at the beginning of the year so I’ve gotten the itch to code again,” Mills said. “Working on personal projects such as Regenerate Thumbnails has been a good way to brush off my coding skills in anticipation of returning to work. Plus it’s just fun to code again!”