Quick Verdict
Use JPG when…
Use JPG for photographs, background images, and any visual content that isn't a small icon. JPG has no role in icons.
Use ICO when…
Use ICO for Windows application icons and website favicons. ICO is the required format for the Windows shell and classic browser favicons — nothing else works in these contexts.
JPG vs ICO: Feature Comparison
| Feature | JPG | ICO |
|---|---|---|
| Purpose | Photographs and web images | Windows icons and favicons |
| Supported sizes | Any size | 16×16 to 256×256 (multiple in one file) |
| Transparency | No | Yes (1-bit and 8-bit alpha) |
| Multiple sizes in one file | No | Yes — ICO can embed multiple resolutions |
| Windows Explorer icon | No (JPG cannot be a Windows icon) | Yes — native Windows format |
| Browser favicon | Modern browsers accept JPG favicon | Classic support — IE/Edge required ICO |
| File size | Large relative to icon sizes | Small (multiple icon sizes in ~10–50 KB) |
When JPG wins
- ✓Purpose: Photographs and web images
- ✓Supported sizes: Any size
- ✓Transparency: No
When ICO wins
- ✓Purpose: Windows icons and favicons
- ✓Supported sizes: 16×16 to 256×256 (multiple in one file)
- ✓Transparency: Yes (1-bit and 8-bit alpha)
Frequently asked questions
How do I convert JPG to ICO for a favicon?
Online: use a favicon generator (favicon.io, realfavicongenerator.net) — paste or upload your JPG and download a complete favicon package including ICO, PNG sizes, and manifest. Command line: convert input.jpg -resize 256x256 -define icon:auto-resize='256,64,48,32,16' output.ico (ImageMagick). For professional results, start with an SVG logo rather than a JPG.
Can I use PNG instead of ICO for a favicon?
Yes, modern browsers (Chrome, Firefox, Safari, Edge) accept PNG favicons via <link rel='icon' href='favicon.png'>. For legacy IE11 support, include an ICO file too. The standard best practice is to have both: favicon.ico (for legacy) and apple-touch-icon.png (for iOS home screens).
More comparisons
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