YouTube is rolling out a new “Test and Compare” feature for video thumbnails, a long-awaited tool that will enable creators to A/B test thumbnail images and optimize for increased watch time.

YouTube first announced the thumbnail testing capability in June 2022, recognizing the importance of engaging thumbnails in driving viewership. After persistent requests from creators, YouTube has now outlined its rollout plan.

According to the company’s video announcement, the “Test and Compare” feature will allow channel managers to upload and compare the performance of up to three thumbnail images per video. These thumbnails will be evenly sampled with YouTube viewers, and the platform will select a winning thumbnail based on which variant generates the highest share of watch time.

“YouTube will show your chosen thumbnails evenly across your video’s viewers and will select a winning thumbnail based on which one generates the most watch timeshare,” the company stated in the video, emphasizing its focus on optimizing for watch time as the key metric to guide successful content strategies.

The thumbnail testing tool is currently available to creators with access to YouTube’s “Advanced Features,” which requires account verification through a phone-based process to confirm the user’s identity.

While the feature is still in its early stages, YouTube took notes that popular creators like MrBeast routinely test and compare up to 20 thumbnail variations for each video upload, underscoring the potential impact of effective thumbnails.