Social Media Strategy

YouTube Thumbnail Best Practices and How to A/B Test

Updated 10 min read
Illustration of two abstract widescreen thumbnails hanging from a balance scale, one side slightly higher, with the title 'YouTube Thumbnail Best Practices and How to A/B Test'

YouTube’s thumbnail best practices come down to six habits: decide who the video targets, use the rule of thirds, add readable text and branding, keep the design simple, make the image as large as possible and keep testing older thumbnails. Checked against YouTube Help: Thumbnail & title tips Two rules frame them: custom thumbnails need a verified account, and YouTube’s Thumbnails policy bans misleading images.

These YouTube thumbnail best practices cover the click side of our plan for growing a YouTube channel: design, eligibility, Shorts and testing. Pixel dimensions and file limits have their own page, YouTube thumbnail size.

Table of Contents

YouTube thumbnail best practices: what makes a good thumbnail?

One aimed at the video’s intended audience that shows what is really in the video. YouTube’s tips start with deciding who the video targets, and its Thumbnails policy bans misleading thumbnails. Checked against YouTube Help: Thumbnails policy

How to make a good YouTube thumbnail, in the order YouTube’s tips give the habits:

  1. Decide who the video targets.
  2. Use the rule of thirds.
  3. Add readable text and branding.
  4. Keep the design simple.
  5. Make the image as large as possible. Pixel dimensions are on our YouTube thumbnail size page.
  6. Keep testing older thumbnails. Changing a title or thumbnail may re-rank a video, YouTube says, because viewers respond to it differently. Checked against YouTube Help: YouTube performance FAQ & Troubleshooting

The thumbnail sits next to the title, and the same YouTube page gives title tips too: be accurate, be succinct with the most important words first (episode numbers and branding at the end), and limit ALL CAPS and emoji. Checked against YouTube Help: Thumbnail & title tips

How do you add a custom thumbnail in YouTube Studio?

On a computer, open the video from YouTube Studio’s Content list and click Upload file under Thumbnail, or Get suggestions to have YouTube generate options. Shorts have their own tab in the same list. YouTube notes that thumbnail changes can take time to appear.

On a computer: Video thumbnail:

  1. Sign in to YouTube Studio.
  2. From the left menu, select Content.
  3. Go to the video you'd like to edit > click the edit icon.
  4. Below "Thumbnail," click Upload file to create a custom video thumbnail from an image on your device or select Get suggestions to generate a thumbnail.
  5. Click SAVE.

On a computer: Short thumbnail:

  1. Sign in to YouTube Studio.
  2. From the left menu, select Content > Shorts at the top.
  3. Go to the Short you'd like to edit > click the edit icon.
  4. Below "Thumbnail," click Upload file to create a custom Shorts thumbnail from an image on your device. For uploaded files, the recommended aspect ratio is 9:16.
  5. Click SAVE.

Checked against YouTube Help: Add custom thumbnails on YouTube.

Ask Studio, inside the publishing workflow, can also suggest thumbnails from a prompt, using the video’s transcript and themes, and you refine them with follow-up prompts. Checked against YouTube Help: Add custom thumbnails on YouTube YouTube lists AI help with a thumbnail among the uses that don’t need its AI disclosure, though the Thumbnails policy still applies. Checked against YouTube Help: Disclosing use of GenAI content

Why can’t I upload a custom thumbnail?

Usually because the account isn’t verified yet. YouTube says uploading your own thumbnail needs a verified account, and until then you can only choose an auto-generated suggestion. Checked against YouTube Help: Add custom thumbnails on YouTube Custom thumbnails are an intermediate feature, unlocked by verifying a phone number. Checked against YouTube Help: Learn about feature access for YouTube Creators

On a computer: YouTube Studio on a computer:

  1. On a computer, sign in to YouTube Studio.
  2. Click Settings.
  3. Click Channel.
  4. Click Feature eligibility, then Intermediate features, then VERIFY PHONE NUMBER.
  5. Enter a phone number. We'll send a verification code by text or phone call to that number.

On a mobile device (Android and iPhone variants match):

  1. Go to m.youtube.com/verify on your mobile device. Sign in if you're prompted to do so.
  2. Choose how to get your verification code.
  3. Enter the 6-digit verification code.

Checked against YouTube Help: Get access to intermediate and advanced features.

A phone number can verify no more than 2 channels per year. Checked against YouTube Help: Verify your YouTube account The full walkthrough is in how to verify your YouTube account.

Already verified? A channel can upload only so many custom thumbnails a day, a number YouTube doesn’t publish that varies by country, region and channel history and drops with Community Guidelines strikes. If you see “Daily custom thumbnail limit reached”, YouTube says to try again in 24 hours. Checked against YouTube Help: Add custom thumbnails on YouTube

Can you add a custom thumbnail to YouTube Shorts?

Yes, but YouTube’s pages describe the rules differently. The Help Center says custom Shorts thumbnails need a verified account and can be added only in YouTube Studio on a computer. Checked against YouTube Help: Add custom thumbnails on YouTube YouTube’s 24 July 2026 blog post says YouTube Partner Program creators can upload them, expanding to more creators over time, and that desktop now offers three suggested Shorts frames. Checked against YouTube Official Blog: New thumbnail updates in YouTube Studio (24 Jul 2026)

The YouTube app does something different: you pick a frame of the Short as its thumbnail, before or after uploading, and can add text and filters. YouTube’s Create Shorts article says that thumbnail can be edited only in the app, not in Studio. Checked against YouTube Help: Create YouTube Shorts For the rest of the format, see our YouTube Shorts best practices.

How do I A/B test YouTube thumbnails?

Use A/B test titles & thumbnails in YouTube Studio on a computer; YouTube’s Test & compare help article now redirects to it. You can test up to 3 titles, 3 thumbnails or 3 title-and-thumbnail pairs. Checked against YouTube Help: A/B test titles & thumbnails YouTube picks the winner by watch time share, not click-through rate, and a test can take a few days or up to two weeks. Checked against YouTube Help: A/B test titles & thumbnails

The tool needs advanced features and isn’t available for Shorts, scheduled live streams, Premieres until they end, or videos that are made for kids, for mature audiences or private.

On a computer: YouTube Studio:

  1. Sign in to YouTube Studio.
  2. Select the video you want to test. Test a new video: From the upper right corner, click CREATE > Upload videos. Then upload the video. Test an existing video: From the left menu, click Content. Click the video you'd like to edit.
  3. In the Title box or under Thumbnail, click A/B Testing.
  4. Select either Title only, Thumbnail only, or Title and thumbnail.
  5. Upload up to 3 thumbnails and/or titles to test.
  6. Click Done.

Checked against YouTube Help: A/B test titles & thumbnails.

Results read Winner, Performed Same or Inconclusive, and with no clear winner the first thumbnail you uploaded is shown. If any test thumbnail is smaller than YouTube’s recommended size, YouTube downscales all of them, so upload every option at full size; the numbers are in our YouTube thumbnail size guide. Checked against YouTube Help: A/B test titles & thumbnails Changing the title or thumbnail during a test stops it. Checked against YouTube Help: A/B test titles & thumbnails

Click-through rate still has a job: YouTube suggests checking it on Home and Suggested in a video’s first 24 hours, and in the Subscriptions feed for subscribers. Checked against YouTube Help: Thumbnail & title tips The rest of the funnel, impressions and watch time, is in how to get more views on YouTube.

What thumbnails break YouTube’s rules?

YouTube’s Thumbnails policy bans thumbnails showing pornography, sexual acts, nudity, shocking violence, gore or vulgar language, and thumbnails that mislead viewers about what is in the video. A violating thumbnail can be removed and earn a strike; repeat offenses may lead to losing custom thumbnail privileges for 30 days or even account termination. Checked against YouTube Help: Thumbnails policy

Short of the policy line, YouTube tells creators to avoid titles and thumbnails that are clickbait, shocking or “loud” (ALL CAPS or !!!!!), because they can turn viewers away. Checked against YouTube Help: YouTube performance FAQ & Troubleshooting

See what Outfeed AI sends with a YouTube upload

YouTube thumbnail FAQ

What makes a good YouTube thumbnail?

YouTube’s Thumbnail & title tips page lists six habits: decide who the video targets, use the rule of thirds, add readable text and branding, keep the design simple, make the image as large as possible and keep testing older thumbnails. YouTube’s Thumbnails policy also bans thumbnails that mislead viewers about what is in the video.

Why can’t I upload a custom thumbnail?

Usually because the account isn’t verified: YouTube says custom thumbnails need a verified account, and they unlock as an intermediate feature when you verify a phone number. Channels also have a daily custom thumbnail limit that YouTube doesn’t publish; if you see ‘Daily custom thumbnail limit reached’, YouTube says to try again in 24 hours.

How do I A/B test YouTube thumbnails?

In YouTube Studio on a computer, open the video, click A/B Testing under Thumbnail and upload up to 3 thumbnails. The tool needs advanced features and isn’t available for some videos, including Shorts. YouTube picks the winner by watch time share, not click-through rate, and a test can take a few days or up to two weeks.

Can you add a custom thumbnail to YouTube Shorts?

Yes, within limits YouTube describes differently. Its Help Center says custom Shorts thumbnails need a verified account and YouTube Studio on a computer; its 24 July 2026 blog post says YouTube Partner Program creators can upload them, expanding over time. In the YouTube app you can pick a frame of the Short as its thumbnail.

Should I change thumbnails on old videos?

YouTube suggests it: its thumbnail tips include continuing to test older thumbnails. Changing a title or thumbnail may re-rank a video, YouTube says, because viewers respond to it differently, not because of the edit itself. On an existing long-form video, A/B testing compares up to 3 thumbnails.

youtube youtube thumbnails youtube studio a/b testing click-through rate