YouTube Thumbnail Quality Enforcer — rainbowrad

YouTube Thumbnail Quality Enforcer improves video thumbnail clarity on youtube.com by automatically forcing higher-quality thumbnail versions.

The extension includes a simple on/off toggle and lets the user choose between three thumbnail quality levels:
- Maximum (maxresdefault)
- Standard (sddefault)
- Medium (hqdefault)

Thumbnail requests to i.ytimg.com are cleaned and rewritten to the selected quality level. In addition, the extension monitors the page in real time so that thumbnails loaded later by YouTube's single-page application are also corrected automatically.

All settings are stored locally in the browser. The extension does not require an account and does not collect or transmit personal data.