When to use it
Use this tool before you upload a thumbnail to YouTube. It checks the size, shape, file size and file type against YouTube’s rules, and shows how the thumbnail looks next to your title on the home page, in dark mode and at the small sizes used in sidebars and phone search results.
How to use it
- Click Choose thumbnail or drag and drop an image. JPG, PNG, GIF and WebP up to 10 MB can be checked.
- Type your Video title and Video length so the previews look real.
- Read the checks for resolution, minimum width, aspect ratio, file size and file type.
- Look at the previews: Home page, light, Home page, dark mode and Small sizes (sidebar, search on phone).
- Click Try another image to compare a different version.
Worked example
You made a thumbnail at 1920 × 1080 pixels and saved it as a PNG of 3.4 MB. The tool says the resolution meets the recommended 1280 × 720 and the aspect ratio is 16:9, but the file size is over YouTube’s 2 MB limit.
In the small preview, the text on the right is hidden under the 12:34 length badge, and the thin font is hard to read. You move the text to the left, make it bolder, and export a JPG at high quality, which comes out well under 2 MB. The checks all pass.
Light and dark mode
Many viewers use YouTube in dark mode. A thumbnail with a black background can blend into the dark page, while a white one can look washed out in light mode. Check both previews and add a border or a brighter subject if it disappears in either.
Design tips
- Use three to five words at most. Big, bold text reads at every size.
- Show a clear face or object. Close-ups stand out in a busy feed.
- Use strong contrast. Light text on a dark background, or the other way round, works in both light and dark mode.
- Keep the bottom right clear. That is where the length badge goes.
Common mistakes
- Saving a huge PNG. Photos are usually much smaller as JPG with no visible difference.
- Using a different shape. A square or tall image gets black bars or cropping.
- Repeating the title. The thumbnail and title are seen together, so make them work as a pair, not say the same thing.
Fixing problems
If the file is too large, try the Compress Image tool. If the shape is wrong, crop the image to 16:9 before uploading.