YouTube thumbnail size
3840 × 2160 px · 16:9 · thumbnail
3840 × 2160
The details
YouTube's current guidance is 16:9 at up to 3840×2160 with a minimum width of 640px — the long-standard 1280×720 still qualifies. JPG, GIF or PNG; uploads are capped at 2MB on mobile and 50MB on desktop.
Source: support.google.com · checked 2026-07-04