What is PNG?
PNG is a lossless raster format: every pixel is kept exactly, and it supports full transparency (alpha channel). It is the standard for logos, screenshots, icons and graphics with text or sharp edges. PNG is best for logos, screenshots, graphics with text and anything that needs a transparent background. PNG files of photos are large, because lossless compression cannot discard fine detail the eye does not notice.
What is ICO?
ICO is the icon format used by Windows and by website favicons. One ICO file can hold several sizes of the same icon (for example 16, 32, 48 and 256 pixels), and the system picks the best one. ICO is best for website favicons and Windows application or folder icons.
When should you convert PNG to ICO?
- You need a favicon.ico for your website so the browser tab shows your logo.
- You want a custom icon for a Windows folder, shortcut or application.
- Your CMS or hosting panel asks for an .ico file.
Tips for the best result
Start from a square PNG of at least 256 × 256 px with a transparent background. Non-square images are centred on a transparent square. Tick the sizes you need — 16, 32 and 48 px cover browser tabs and Windows; 256 px is used for large Windows icons.
PNG vs ICO at a glance
| PNG | ICO | |
|---|---|---|
| Type | Raster | Raster container |
| Compression | Lossless | PNG or BMP inside |
| Transparency | Yes (full alpha) | Yes |
| Animation | No (APNG rarely used) | No |
| Compatibility | Universal | Windows and browsers (favicons) |
| Best for | Logos, screenshots, graphics with text and anything that needs a transparent background | Website favicons and Windows application or folder icons |