YouTube's official recommendation for custom thumbnails is 1280×720 pixels (HD) at a 16:9 aspect ratio. This is the same as the maxresdefault thumbnail that Tube Fetch provides.
Why 1280×720 Is the Best Size
- Matches YouTube's native HD video resolution
- Displays sharply on all screen sizes from mobile to 4K monitors
- Required for YouTube to show custom thumbnails in HD
- Minimum recommended: 640×360 (standard)
File Size Limit
Custom thumbnails must be under 2MB. JPEG is the most common format and offers the best compression for photos and illustrated thumbnails.
Aspect Ratio Is Critical
Always use 16:9 (widescreen). Thumbnails that aren't 16:9 will show black bars when displayed in YouTube's player and search results, which hurts visual appeal and click-through rates.
Text and Contrast Tips
For thumbnails designed to attract clicks, keep text large enough to read at thumbnail size (roughly 1/4 of the total height) and use high-contrast colors against your background. Faces with strong expressions consistently outperform text-only thumbnails in click-through rate studies.