I'm preparing a series of coding tutorials and want to include professional-looking thumbnails. While I can manually screenshot frames, it's often low resolution or inconsistent. Are there any reliable tools or workflows to get the official high-quality YouTube cover images?

I also wrote a short guide on "10 Thumbnail Design Tricks That Double Click-Through Rate" if anyone's interested (happy to share). For my workflow, I usually use YouTube-Cover.com — a free tool that extracts HD thumbnails (1080p, 720p) by just pasting the video URL. It's been a time-saver.

Any recommendations or best practices you follow for thumbnail optimization?

Thanks in advance!