Checked on October 4, 2026, based on the YouTube Help article "Add video thumbnails".
Why 2 MB?
Phones have less memory and often slower networks than computers, so YouTube sets a smaller limit for mobile uploads. Files over 2 MB are rejected in the app. If you might ever upload from your phone, make the thumbnail under 2 MB from the start.
The fastest way
- Design your thumbnail in the YouTube Thumbnail Maker.
- In Save, choose JPG.
- Turn on auto-compress with a 2000 KB target; it lowers quality automatically until the file fits.
Doing it by hand, in this order
| Step | What to do | Effect |
|---|---|---|
| 1 | Switch to JPG | Photo-based images get much smaller than PNG |
| 2 | Lower the resolution (3840×2160 → 1920×1080 or 1280×720) | Fewer pixels, smaller file |
| 3 | Set quality to 80–90% | Hardly visible difference |
| 4 | Simplify heavy gradients, noise and shadows | Complex textures compress poorly |
If text edges start to look smeared, raise quality and lower the resolution instead. For mostly text on flat colors, PNG can actually be sharper and smaller.
Size limits on other platforms
| Use | Limit (as of 2026-10-04) |
|---|---|
| YouTube custom thumbnail (mobile) | 2 MB |
| YouTube custom thumbnail (desktop) | 50 MB |
| YouTube channel banner | 6 MB |
Thumbnails are loaded again and again in small lists, so YouTube limits them more strictly than banners, which load once per page.
When compression doesn't help
Re-compressing an already compressed JPG barely changes its size. Go back to the original photo or design file and lower the resolution. Starting a new design at 1280×720 avoids the problem entirely.
Lossy vs. lossless
JPG is lossy: it throws away detail you can't easily see, which makes files much smaller. PNG is lossless: it keeps every pixel, so photos become large. Thumbnails are usually text on a photo, so JPG is the better choice most of the time.
Good vs. bad
- Good: 1280×720, JPG, quality 85%, roughly 300–700 KB.
- Bad: 3840×2160, uncompressed PNG, 5–15 MB (fails on mobile).
Common mistakes
- Uploading a screenshot that saved as PNG. Convert it to JPG.
- Compressing so hard that text edges blur. Don't go below about 70% quality.
- Keeping the full original resolution when 1280×720 is enough.
FAQ
Will compressing to 2 MB make my thumbnail look bad?
Usually not. At 1280×720, a JPG at 80–90% quality is typically a few hundred KB and looks the same on screen.
Is the limit 2 MB or 50 MB?
Both: 2 MB when uploading from the mobile app and 50 MB from a computer. Staying under 2 MB means it uploads anywhere.
Why is my 1280×720 PNG over 2 MB?
PNG stores every pixel without loss, so photo backgrounds make it large. Save the same design as JPG and it will usually drop well below 1 MB.