How to convert PNG to ICNS
Choose a square PNG, check how it reads at small sizes, then download the ICNS file. The converter creates standard and Retina variants from 16 to 1024 pixels and preserves transparency. Conversion happens in your browser.
What is an ICNS file?
ICNS is a macOS icon container that holds multiple representations of one image. macOS can choose a representation for the size and scale it needs. Start with a 1024 × 1024 PNG and check that the design is recognizable at 16 pixels.
When should I use ICNS or an Xcode asset?
Use ICNS when a Mac packaging workflow asks for a single .icns file. If your Xcode project uses an AppIcon asset catalog or an Icon Composer file, follow the input format for that workflow. Apple Icon Composer