TikTok's thumbnail is the first thing viewers see before the video autoplays. In search results and profile pages, it's the ONLY thing they see. A single-frame thumbnail from a 60-second video captures at most one moment. A grid thumbnail captures 3–4 key moments — the hook, the middle reveal, the satisfying ending — telling the full story before anyone presses play.\n\nEffective TikTok grid strategies: (1) the transformation sequence — before/during/after in a 1×3 vertical strip (perfect for skincare, cleaning, renovation), (2) the reaction sandwich — setup → reaction → result in 1×3, (3) the product showcase — 2×2 grid showing four angles or color variants, (4) the tutorial preview — 1×3 showing step 1 → step 2 → step 3.\n\nExport at 1080×1920px (9:16 portrait) — TikTok's native format. Use 2–4px white spacing between cells. For text overlays, add your hook phrase ('You won't believe #3') on the grid before exporting. MergeFrame processes everything locally — your unreleased content stays private.