YouTube thumbnail downloader
What this downloader exposes
Public thumbnails live on Google's CDN at predictable paths keyed by video ID—sizes range from tiny previews (default) through SD/HQ frames up to maxresdefault when Google captured a 1280×720 still. Not every video ships a max-resolution asset; missing URLs simply 404.
Rights & etiquette
Thumbnails inherit the video's copyright—blog hero reuse still needs permission or fair-use analysis. Pair downloads with Image optimizer before CMS upload and cite creators.