FrameSnap for YouTube 作者： EasyPlugins

Adds a camera button to the YouTube player's right-side controls. Click the button or press S to instantly capture the current video frame in its original resolution.

Features:
One-click screenshot of any video frame
Saves as PNG in full video resolution
Keyboard shortcut: S
Camera flash animation on capture
Filename includes video title and timestamp
Works in fullscreen mode

The extension works only on youtube.com video pages and does not collect or transmit any data.