What is a .ICNS file?

ICNS is the macOS icon format, storing an app icon at multiple resolutions in one file.

Full name

Apple Icon Image

Developed by

Apple

Released

1991

Extension

.icns

MIME type

image/icns

Transparency

Yes

How to open a ICNS file

ICNS is used by macOS; it opens in Preview, Icon Composer and many editors.

What ICNS files are used for

App icons

Crisp icons at every required size.

Favicons

Browser-tab and bookmark icons.

UI assets

Cursors, toolbars and system glyphs.

Strengths & limitations

✔ Strengths	✖ Limitations
Supports transparency	Less common outside its niche

Tools for this format

Convert, compress and edit — free, in your browser.

SVG to ICNSmacOS icon ICO to ICNSWindows → Mac PNG to ICNSmacOS icon JPG to ICNSmacOS icon JPEG to ICNSmacOS icon ICNS to PNGMac → PNG ICNS to ICOMac → Windows ICNS to SVGMac → vector

Need more than a conversion?

Remove the background from ICNS images, upscale to 4K, or generate new visuals with SharkFoto AI.

Try AI tools AI Effects

Frequently asked questions

ICNS is the macOS icon format, storing an app icon at multiple resolutions in one file.

ICNS is used by macOS; it opens in Preview, Icon Composer and many editors.

ICNS is optimised for its specific use rather than strictly lossless storage.

Use SharkFoto's free tools — upload your ICNS file and convert it to a more convenient format in seconds. It's free, processed securely and never stored.

Yes — ICNS supports transparent backgrounds.

Related formats

.ICO .CUR