🎬 Why I Built ThumbGrab

I frequently needed to download YouTube thumbnail images and had been using various third-party services for this purpose. However, since I often perform this task, I wanted a more convenient solution. Therefore, I created a simple tool tailored to my needs. ThumbGrab automatically fetches the highest resolution thumbnail available, displays the video title, and allows you to download it safely—no API required.

The name “ThumbGrab” is a simple combination of “thumbnail” and “grab.” It clearly reflects what the tool does while keeping the name short, catchy, and easy to remember.

⚙ Key Techniques Used

The core logic is straightforward: YouTube thumbnails can be accessed directly via predictable image URLs. That means there’s no need for a full API—just a properly constructed URL is enough to retrieve the image, making this a purely client-side tool.

Since not every video offers a max-resolution image, the script tries several sizes in order (maxresdefault, sddefault, etc.) and uses the first available one. This fallback mechanism ensures the best quality possible without breaking.

For video titles, I chose not to use the official YouTube Data API because it requires an API key and setup. Instead, I used noembed.com, a lightweight oEmbed service that returns basic metadata like titles. It’s fast, reliable, and perfect for this use case.

🎯 Design Considerations

The frontend is built with plain HTML, CSS, and JavaScript. CSS styles are minimal and match the visual language of other Dottiq tools. For downloading, I used fetch() and Blob to trigger a proper download dialog—even on browsers like Safari that don’t fully support <a download>.

I initially placed the tool at the root level, but later moved it to /tools/thumbgrab/ to match the structure of other tools. An English version is also available at /en/tools/thumbgrab/, making it easy to share internationally.


🔧 Technologies & Resources Used

  • Thumbnail source: https://img.youtube.com/vi/【ID】/maxresdefault.jpg
  • Title metadata: noembed.com (YouTube oEmbed API)
  • Download method: fetch() + Blob + a.download
  • Fallback logic: Tries available sizes in descending quality order
  • Languages used: HTML / CSS / JavaScript (Vanilla)

Try ThumbGrab here