Apple does not publish a list of types. This one comes from the
libicns library, the
icnsutil project and its
survey of the icons in macOS releases.
The types below were also found in the .icns files checked on macOS for this
reference, except ICON, icm4 and FF DA 3A 5D. An
element with a type not listed is reported, and kept as bytes.
PNG and JPEG 2000
The data is a complete PNG or JPEG 2000 file. A double-density element has two pixels per point on each side.
| Type | Pixels | Density | Also |
|---|---|---|---|
icp4 | 16 × 16 | @1x | Or three packed channels |
icp5 | 32 × 32 | @1x | Or three packed channels |
icp6 | Sources disagree | Given as 48 by icnsutil and 64 by others | |
sb24 | 24 × 24 | @1x | |
SB24 | 48 × 48 | @2x of 24 × 24 points | |
icsB | 36 × 36 | @2x of 18 × 18 points | |
ic11 | 32 × 32 | @2x of 16 × 16 points | |
ic12 | 64 × 64 | @2x of 32 × 32 points | |
ic07 | 128 × 128 | @1x | |
ic13 | 256 × 256 | @2x of 128 × 128 points | |
ic08 | 256 × 256 | @1x | |
ic14 | 512 × 512 | @2x of 256 × 256 points | |
ic09 | 512 × 512 | @1x | |
ic10 | 1024 × 1024 | @2x of 512 × 512 points | Apple says the 1024 × 1024 size is replaced by 512 × 512 at 2x |
ARGB
Each holds four packed channels after the letters
ARGB, or a PNG or JPEG 2000 file.
| Type | Pixels | Density |
|---|---|---|
ic04 | 16 × 16 | @1x |
ic05 | 32 × 32 | @1x |
icsb | 18 × 18 | @1x |
24-bit and 8-bit masks
Three packed channels and a separate 8-bit mask of the same size.
| Colour | Mask | Pixels |
|---|---|---|
is32 | s8mk | 16 × 16 |
il32 | l8mk | 32 × 32 |
ih32 | h8mk | 48 × 48 |
it32 | t8mk | 128 × 128 |
Indexed and 1-bit
The oldest element types, with no compression.
| Type | Pixels | Storage |
|---|---|---|
ICON | 32 × 32 | 1 bit, no mask |
ICN# | 32 × 32 | 1 bit and 1-bit mask |
icm# | 16 × 12 | 1 bit and 1-bit mask |
icm4 | 16 × 12 | 4 bits |
icm8 | 16 × 12 | 8 bits |
ics# | 16 × 16 | 1 bit and 1-bit mask |
ics4 | 16 × 16 | 4 bits |
ics8 | 16 × 16 | 8 bits |
icl4 | 32 × 32 | 4 bits |
icl8 | 32 × 32 | 8 bits |
ich# | 48 × 48 | 1 bit and 1-bit mask |
ich4 | 48 × 48 | 4 bits |
ich8 | 48 × 48 | 8 bits |
Other elements
| Type | Holds |
|---|---|
TOC | A table of contents |
icnV | A version number |
name | A short name |
info | A binary property list |
sbtp | A nested set of template icons |
slct | A nested set of selected icons |
FD D9 2F A8 | A nested set of dark-mode icons. The type is these four bytes |
FF DA 3A 5D | Listed by the icnsutil survey with no description; not found in the files checked here |