Why Do This in Your Browser?
Contact sheets — also called sprite sheets, preview grids, or video thumbnails — are how every download site and torrent index lets you see a video's content at a glance. They're trivial to make with FFmpeg's `tile` filter, and yet most online tools wrap them in upload-process-download workflows that turn a 5-second operation into a 5-minute one.
FFmpeg.wasm with the tile and scale filters runs the whole operation locally. The tool extracts N evenly-spaced frames (or frames at exact timestamps), scales each to the target thumbnail size, then tiles them into an R×C grid with optional borders, labels, and timestamps. Output is a single PNG or JPG.
How It Works
Pick the grid shape (3×3, 4×4, 4×3, custom rows × columns), thumbnail width in pixels, and frame selection mode (evenly distributed, fixed interval, or exact timestamps). The tool computes the frame timestamps, runs FFmpeg.wasm with `select='eq(n,0)+eq(n,F)+...'` and the `tile` filter, scales the final composite, and outputs the contact sheet.
Style options: solid or transparent border between thumbnails (1–10px width), optional timestamp overlay per frame, optional video filename in the corner. JPG output is smaller (good for embedding in markdown or sharing); PNG preserves text overlays sharply (good for documentation, archives, video catalogues).
Tip: For individual frame export (not tiled), the Video Frame Extractor tool is the right pick — it exports a zip of separate PNGs. Use this thumbnail-grid tool when you want a single overview image. Pair with the Video Compressor to make the grid file smaller before sharing.
Common Use Cases
How We Compare
Honest read on free, paid, and self-hosted options for this kind of job: