Common size
1280 × 720, with a 16:9 ratio.
Why thumbnail view matters so much
Most people do not see the full-size image. They see a very small preview. If the text is thin, the edges are noisy, or the subject is too loose, the first impression falls apart.
More practical export advice
- Keep the main subject focused instead of spreading too much information across the frame.
- Avoid placing text too close to the edges.
- Check the horizontal crop before exporting to make sure the key scene survives.