Video Thumbnail Generator
Runs in your browserExtract thumbnails from any video, create contact sheets, and build slideshow or overlay videos. 100% browser-based — your videos never leave your device.
How It Works
Upload Video
Drag and drop or click to upload. Supports MP4, WebM, MOV, MKV.
Configure & Extract
Choose count, timestamps, output size, and format. Extract precise frames with WebCodecs.
Download & Create
Download thumbnails, generate contact sheets, or create slideshow and overlay videos.
Frequently Asked Questions
What formats are supported?
MP4, WebM, MOV, MKV, and most common video formats. Output thumbnails can be PNG, JPEG, or WebP.
How precise is the frame extraction?
With WebCodecs (Chrome, Edge, Firefox 130+), extraction is frame-accurate with microsecond precision. On older browsers, it falls back to keyframe-based seeking which is less precise but still functional.
What is a contact sheet?
A contact sheet combines all extracted thumbnails into a single grid image with timestamp labels. Useful for video overviews, storyboards, and sharing.
Can I create a video from the thumbnails?
Yes! The slideshow feature creates a video that plays each thumbnail for a configurable duration with fade transitions. The overlay feature burns thumbnails into the original video as an intro or picture-in-picture.
Is my video uploaded to a server?
No. Everything runs in your browser using WebCodecs and MediaBunny. Your video never leaves your device.
Built With Open Source
Pure TypeScript media toolkit with WebCodecs for hardware-accelerated frame decoding
Browser-native hardware-accelerated video encoding and decoding
Frame rendering, contact sheet generation, and image export
Slideshow video creation via canvas capture stream