How to make a thumbnail
- Pick a layout: text left with the subject right, the reverse, big centered text, or text along the bottom. Every element can still be dragged on the preview.
- Set the background: a solid color, a two-color gradient, or a photo (zoom and drag to frame it; darken it if the text needs help).
- Add a subject: a cut-out PNG of a face or product. The outline slider puts a solid edge around it.
- Write two to four words per line, one line per row. The text shrinks automatically to fit the width you allow, so a long line never runs off the frame.
- Check the small previews and the contrast line, then download the JPG.
What YouTube asks for
YouTube’s help page on custom thumbnails recommends a resolution of 1280×720 with a minimum width of 640 pixels, and a file under 2 MB for video thumbnails (10 MB for podcasts). It also notes that for vertical videos a 16:9 custom thumbnail is replaced by an automatic 4:5 one on the home, explore and subscription pages, so this tool is for regular landscape videos. Exports here are always exactly 1280×720.
What we tested
On October 14, 2026 we drove the tool in Chromium and checked every download with Pillow: dimensions, file type from the file’s own signature, and size in bytes.
| Case | Download | Size | Result |
|---|---|---|---|
| Gradient, text, badge (default) | JPG 1280x720 | 77,493 bytes | quality 95 |
| Photo background + cut-out subject | JPG 1280x720 | 210,561 bytes | quality 95 |
| Same, as PNG | PNG 1280x720 | 1,005,395 bytes | under 2 MB |
| Random-noise background (worst case) | JPG 1280x720 | 679,744 bytes | quality 95, under 2 MB |
| Random-noise background as PNG | PNG 1280x720 | 2,103,985 bytes | over 2 MB, flagged |
The quality search itself is tested separately with a stand-in encoder whose files shrink 10% per step from 3 MB: it stops at quality 75, the first step under 2,000,000 bytes, and reports failure only if the file is still too big at quality 40. The preview and the download are drawn by the same function: the exported PNG matched the on-screen preview canvas at 99.0 dB PSNR. Dragging the text on the preview moved it by the distance dragged (textX 0.06 to 0.16 for a drag of a tenth of the width), and the page fitted a 390 px phone screen with no errors.
Making text readable at thumbnail size
Most people see a thumbnail at a fraction of its size, so check the 320×180 preview rather than the large one. Big, heavy type with a thick dark outline survives shrinking; thin type and long phrases do not. The contrast line measures your text against the actual pixels behind it, which is more useful than comparing two swatches: the same white text can be 8:1 over a dark corner and 1.5:1 over a bright sky.
Sources
Checked on .
Frequently Asked Questions
Built by Derek Giordano · Part of Ultimate Design Tools