Correct dimensions for YouTube thumbnails
Use 1280×720px (16:9) for optimal quality on all devices. Keep file size under 2MB. Use high contrast text, faces with emotion, and bright colors. Avoid placing important elements in the bottom-right corner (where the timestamp appears). Test thumbnails on mobile — 70% of views are on phones.
Keep text and key visuals in the center 80% of the thumbnail. YouTube crops edges differently on mobile, desktop, and TV. The bottom-right 15% is covered by the video duration badge.