With Chrome 66, Google made some hefty changes to the way autoplaying content works — killing it, essentially. Unfortunately, this has broken a number of extensions (such as Imagus) preventing them from interacting with animated, cross-site images.
Until extension developers figure out a workaround (if it's even possible), you can change Chrome's autoplay behaviour temporarily to address the problem.
You'll need to dive into Chrome's internal flags page and hit up the "Autoplay policy" option:
Then, switch it from "Default" to "No user gesture is required". You'll have to reboot Chrome for the new option to take effect.
After that, the extensions should work again, however, autoplaying content will function as it did pre-Chrome 66.
With Chrome's more recent updates, Google is doing its best to eliminate the greatest annoyances found on the web. In this vein, from version 66 of the browser, autoplaying video will be a thing of the past, with Google soon to clamp down on the media behaviour.
Autoplay policy changes [Google]