YouTube dynamic thumbnails vs A/B testing: what we know so far
YouTube announced dynamic thumbnails, but A/B testing is the thumbnail test you can run in Studio today. Here's what YouTube has said about each.
3 min read ThumbnailsYouTubeStrategyYou can test thumbnails in YouTube Studio today. YouTube Help says: "Creators can test and compare up to 3 different titles and thumbnails." In the Title box or under Thumbnail, the button is **A/B Testing**. Our guide to [A/B testing thumbnails in YouTube Studio](/blog/youtube-studio-thumbnail-ab-testing) walks through the setup.
Dynamic thumbnails are a different story. YouTube has announced them, but there's no Help page for them yet. Here's what each one looks like right now.
What YouTube announced about dynamic thumbnails
YouTube announced dynamic thumbnails at Made on YouTube. [YouTube's post](https://blog.youtube/news-and-events/made-on-youtube-new-tools-power-creation-journey/) gives them one sentence: "You can even generate channel-matched thumbnails or use dynamic thumbnails to have YouTube recommend the best of three options to different segments of your audience."
That's all YouTube has said so far. There's no Help page for it yet.
How A/B testing picks a winner
A/B testing runs every option at once. Help says: "YouTube's A/B tests are true, concurrent A/B/C tests. This means all variations are shown to viewers at the same time."
Some viewers sit out the test. Help says: "We may maintain a small percentage of traffic as a control group of viewers that are excluded from the experiment. The control group will only see the default title and thumbnail."
The winner comes down to watch time. Help says: "When your A/B test is over, the option with the highest watch time will be shown to all viewers." It also says "we optimize tests for overall watch time over other metrics, like click-through-rate."
Not every test ends with a winner. Help says: "If there was no clear “winner,” then the first title or combination of title and thumbnail that you uploaded will be shown to all viewers." So upload your favorite first.
Making three images worth testing
A test is only as useful as the options in it. Help warns: "Testing titles and thumbnails that are too similar to each other can cause tests to run for longer." Change one big thing per option, like the face, the text or the whole concept. Small nudges in color or crop give the test very little to separate.
Keep every option at full size, too. Help says: "If the resolution of any thumbnail is lower than 720p (1280 x 720), all experiment thumbnails will be downscaled to 480p (854 x 480)."
Stuck on a third idea? [YouTube's AI thumbnail generator](/blog/youtube-ai-thumbnail-generator) can draft options for you inside Studio.
If dynamic thumbnails show up in Studio
If dynamic thumbnails appear in your Studio, check YouTube Help for how they work before you rely on them. Until then, A/B testing is the thumbnail test YouTube documents.
Before you start a test, run your three options through [Thumbly Score](/blog/how-to-use-thumbly-score) to pick the ones worth testing.
