How to preview your thumbnail
- 1Choose your thumbnail image or drag the file onto the upload area. It is only read by your browser.
- 2Type the video title and your channel name. Optionally add your channel avatar for a more realistic preview.
- 3Switch between dark and light mode and check every view, especially the small sidebar thumbnail.
- 4Review the technical checks: aspect ratio, resolution, file size, format and title length.
- 5Turn on A/B compare to put two versions side by side in the same layouts.
Why preview before you publish
You design a thumbnail on a big screen, zoomed in, but viewers see it in a grid full of other videos, often on a phone. In the up-next list it takes up about 168×94 pixels: text that looked huge in your editor can turn into a blur.
Seeing the image in a realistic context, next to other videos and with its title, is the fastest way to tell whether it stands out, whether the text is readable, and whether the title and image complement each other instead of repeating the same message.
Tips for thumbnails that get clicks
- High contrast. Separate the subject from the background with opposing colors: light on dark, warm on cool. Remember the YouTube interface can be white or near-black.
- Three words, max. Short, large, bold text. The thumbnail complements the title; it does not need to repeat it.
- A face with emotion. A close-up of an expressive face (surprise, curiosity, joy) builds connection. The expression should match the topic of the video.
- One focal point. A single main element that clearly stands out. Too many elements compete with each other and vanish at small sizes.
- Readable when small. If the idea is not clear at the 168×94 sidebar size, simplify.
- Keep the bottom-right corner clear. That is where YouTube shows the video length; avoid putting text or key details there.
- Stay consistent. Similar colors, fonts and framing across videos help viewers recognize your channel in a crowded feed.
YouTube thumbnail requirements
YouTube recommends thumbnails at 1280×720 pixels (minimum width of 640 pixels), in a 16:9 aspect ratio, up to 2 MB, in JPG, PNG or GIF format. Images in other formats, such as WebP, AVIF or HEIC, must be converted before uploading. To upload custom thumbnails, your channel needs to be verified.
Titles can be up to 100 characters long, but feeds usually show only the first 60 to 70, depending on the screen. Put the most important words first.
Compare two versions
When you are torn between two ideas, use compare mode to see them side by side in the same layouts. A visual comparison helps you drop the weaker version, but your audience has the final word: an A/B test shows which thumbnail gets more clicks from real viewers.