Privacy
ThumbUHD is a utility. You paste YouTube URLs. The browser sends them to PHP so we can extract an ID, call YouTube oEmbed, and fetch public stills from i.ytimg.com. Those requests are not used to build a public library of videos you looked up.
What we process to show a thumbnail
The paste is parsed for an 11-character video ID. We request YouTube’s public oEmbed JSON for title and author when the video is public. We request public JPEG/WebP objects on i.ytimg.com to measure pixels and to proxy a download with a sensible filename. We do not ask you for a Google account. We do not use a YouTube Data API key on this desk.
What stays on your device
Recent lookups shown as “On this device” use localStorage in your browser. Theme preference uses the same. Clear site data and they leave. We do not require accounts.
What we do not keep
Thumbnail bytes are proxied so you can download a file with a sensible name and so the palette/converter can sample a same-origin image. Proxied images are not archived as a gallery on disk after the response.
If the host later adds analytics on this marketing site, that is separate from the YouTube URLs you paste — we do not append our own tracking onto the stills. Questions belong with whoever operates this domain. Related: using thumbnails legally.