The support for newer image types seems to be introduced later than the key field (see previous two points).The 24-bit RGB icons ( is32, il32, ih32, it32) also allow images in JPEG 2000 and PNG format (tested on macOS 10.15.7 and macOS 11).Yet, even the ARGB keys can be displayed on macOS 10.15 if you set a JPEG 2000 or PNG image (see footnote on usage in app packages above). ARGB images are only supported in macOS 11 and newer – macOS 10.15.7 does not display ARGB images.

the ARGB fields also accept files in PNG format – but not vice versa, you can not put ARGB images in any of the PNG-only fields (tested on macOS 11).The ARGB format consists of the ascii values for 'ARGB' and the four compressed channels tightly packed (see Compression).The it32 icon must start with a four-byte header, see footnote above. The 24-bit RGB format consists of the three compressed channels tightly packed (see Compression).The 4-bit an 8-bit icons use a fixed color palette with 16 colors and 256 colors respectively.Mono icons with alpha mask can display three colors: white, black, and transparent.These formats are supported in standalone icns files but do not display properly if used as application icon inside a. Usage unknown, the four zero-bytes can be any value and are quietly ignored. it32 data always starts with a header of four zero-bytes (tested all icns files in macOS 10.15.7 and macOS 11). The value inside the parenthesis is the uncompressed length for ARGB and 24-bit RGB icons. JPEG 2000 or PNG format 'retina' in 10.8)ĪRGB or JPEG 2000 † or PNG † format 'retina') JPEG 2000 † or PNG † format or 24-bit RGB icon Length of data, in bytes (including type and length), msb first The file format consists of an 8 byte header, followed by any number of icons.

Old mac icons download