Video Thumbnail Extractor

A good thumbnail is a sharp, well-lit frame at the right size. This tool takes frames straight from your video — no screenshots, no scaling blur — and saves them as JPG, PNG or WebP, ready for YouTube, Shorts, Reels or a website. It can look for the best frames for you, skipping black fades, motion blur and empty transitions, or grab the exact moments you name. Most MP4, WebM and MOV files are read by your browser's own video player in seconds; AVI, MKV, WMV and other formats go through the ffmpeg engine (about 30 MB, downloaded the first time). Nothing is uploaded.

How to use this tool

1. Choose how to pick frames: the best-looking ones, exact times, or evenly spread.
2. Pick the size: YouTube 1280 × 720, Full HD, 9:16 for Shorts and Reels, square, or the original size.
3. Decide what happens when the video's shape differs: crop to fill, or fit with a blurred copy or coloured bars behind.
4. Choose the video. Compare the thumbnails and download the one you like, or all of them as a ZIP.

Formula

Sharpness score = variance of the Laplacian of a 160-px grey copy (× 0.05 if nearly black or white, × 0.1 if flat)

The Laplacian measures how strongly each pixel differs from its four neighbours, so in-focus frames with clear edges score high and blurred or faded frames score low. "Best" checks at least 16 frames between 5% and 95% of the video, keeps them a little apart in time, and lists them best first. Crop-to-fill scales the frame until it covers the whole thumbnail and trims the overflow equally on both sides.

Example

A 1920 × 1080 clip saved at YouTube size is scaled to exactly 1280 × 720 — same 16:9 shape, nothing cropped. A vertical 1080 × 1920 phone video at the same size is cropped to fill: it is scaled to 1280 × 2276 and the middle 720 px of its height are kept, or, with "Fit, with a blurred copy behind", the whole picture sits in the centre with a blurred, darkened copy of itself filling the sides.