Thumbnails matter
On YouTube, the thumbnail is often the deciding factor in whether someone clicks. The platform recommends 1280 × 720 pixels in a 16:9 ratio: large enough to look sharp on TVs and desktop screens, while matching the shape of the video player so nothing is letterboxed. Thumbnails are also displayed very small in search results and sidebars, which is why bold, high-contrast designs with large text work best.
Preparing a thumbnail
- Design at 16:9. If you design in another ratio, “Crop to fill” will trim the edges; check that no text is lost.
- Mind the timestamp. YouTube overlays the video length in the bottom-right corner, so keep important elements away from it.
- Use JPG for photos and PNG for flat graphic designs, then check the size stays under 2 MB.
Other uses for 1280 × 720
The 16:9 HD frame is everywhere: it is the default slide size in modern presentation software (at a lower pixel density), the frame of 720p video, a common size for blog hero images and link previews on some platforms, and a good wallpaper size for small laptops. Resizing to 1280 × 720 is a convenient way to standardise images for any of these uses.
Checking your thumbnail at small sizes
Most viewers see your thumbnail at a fraction of its full size, often around 168 × 94 pixels in the sidebar or on a phone. After resizing, zoom out or view the downloaded image small to check that the main subject and any text are still clear. If not, simplify the design: fewer words, larger faces and stronger contrast usually perform better than detailed compositions.
How it works
Your image is decoded in a background Web Worker, rotated according to EXIF data, cropped or padded to 16:9, and resampled with the Lanczos3 filter. The output keeps the input format unless you choose another. No upload takes place.
For full HD frames use 1920 × 1080; for link previews on Facebook and LinkedIn use 1200 × 630. To get under YouTube’s 2 MB limit, use the image compressor.