The recommended 유튜브 YouTube thumbnail spec is 1280×720 px (16:9). 1280×720 (16:9), under 2MB, JPG/PNG. The bottom-right corner is covered by the duration badge. Widths under 640px are rejected.
"Fill" center-crops when the ratio differs. "Fit" pads with the chosen color. "Fit width" keeps the height ratio, for detail pages.
Drag the preview of a "Fill" result to move the crop.
JPG, PNG or WebP, quality 50–100. Each result card shows size and weight.
Select several files to convert them to the same spec and download with "Save all".
1280×720 px, ratio 16:9. 1280×720 (16:9), under 2MB, JPG/PNG. The bottom-right corner is covered by the duration badge. Widths under 640px are rejected.
Choose "Fit (padding)" to avoid cropping; with "Fill" you can drag the preview to move the crop.
Upscaling beyond the original blurs. Use the largest original you have; when downsizing, quality 90+ is visually lossless.