YouThumb is a free Chrome extension that helps YouTube creators dramatically improve their click-through rate (CTR) by testing thumbnails in the environment that actually matters: the live YouTube feed. Most creators design thumbnails inside Photoshop, Figma, or Canva — large canvases where every design decision looks amazing. The problem? On YouTube, your thumbnail competes at a fraction of that size, surrounded by thumbnails from creators you've never seen, on a dark or light background you didn't design for. YouThumb bridges that gap.

What it does:
- Preview any thumbnail inside the real YouTube homepage, search results, and sidebar
recommendations
- Compare your design side-by-side with top creators in your niche
- Test in both light mode and dark mode (50/50 of your audience uses each) - Preview your thumbnail exactly as viewers will see it
- Get AI-powered analysis on contrast, readability, and composition

Who it's for:
YouTube creators, video editors, thumbnail designers, agencies managing creator channels, and anyone who cares enough about CTR to test before publishing instead of hoping after.