Controversial: YouTube is walking a fine line. Screw with someone's ability to feed their family and it's easy to understand why some creators are upset. Then again, messing with monetization isn't uncharted territory for the video giant.

YouTube over the next few weeks will carry out an experiment that's already driving a wedge further between the platform and its content creators.

As explained on Google's product forums and reiterated on Twitter, a small group of viewers - 0.3 percent of YouTube's total audience - will see the default, auto-generated thumbnail for all videos across all channels instead of the custom thumbnails uploaded by creators.

Considering YouTube now has over 1.8 billion registered viewers every month, that could equate to more than five million people being affected.

YouTube stressed that it isn't removing the ability to create custom thumbnails but is instead simply testing the effectiveness of auto-generated thumbnails in hopes of improving them in the future.

Thumbnails, along with carefully crafted titles, are arguably a creator's top asset on the platform. Choose the "right" thumbnail and your video will stand out from the crowd; select a mundane preview and it'll get lost in a sea of other videos vying for viewers' attention.

On the flip side, Google's intentions aren't exactly unmerited. YouTube is a notoriously seedy environment dominated by clickbait. Aiming to clean up the misleading mess and improve the user experience is hard to fault... but then again, that's easy to way when you don't have a financial interest in the matter either way.