Online Tool Store
Thumbnail Preview Tester
Preview a thumbnail at the sizes platforms actually render — feed, sidebar, and mobile search — to check whether its text survives.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Social Media
Thumbnail Preview Tester
Frontend preview — no upload or external service.
Preview sizes
Rendered at 360x202, 168x94, and 106x60 — the four-word headline is legible at the first two and illegible at search size.
How the Thumbnail Preview Tester works
- Upload the thumbnail you are about to publish.
- Compare it at all three sizes, especially the smallest one.
- If the text fails at 106 px wide, cut words rather than shrinking the type further.
FAQ
How many words can a thumbnail carry?
Three or four at most, set very large. The smallest render is around a hundred pixels wide, and anything more becomes texture rather than text at that size.
Does the light or dark background matter?
Yes. A thumbnail with white edges dissolves into a light feed and floats oddly in a dark one. Check both, since viewers control the theme, not you.
Is my image uploaded?
No. It is rendered locally in the page for preview only.
How we compare
| Feature | Online Tool Store | The platform itself | A social suite |
|---|---|---|---|
| Real platform pixel sizes | ✓ | ✗ | Sometimes |
| Light and dark backgrounds | ✓ | Manual | ✓ |
| No upload to a platform | ✓ | ✓ | ✗ |
| Instant iteration | ✓ | ✓ | Varies |
Thumbnail Preview Tester exists because thumbnails are designed at full size and consumed at a hundred pixels — the small preview is the one that decides.