Mac OS X Icon Resource Format
Apple
System Files
mime-type/not-avalible
10/09/2021
To edit ICNS file, we strongly recommend installing software that works with ICNS files. Of course, there are probably ICNS Online Editors available, but none of them will be able to provide such a wide range of available options as dedicated software.
The installation of the program that supports the ICNS file does not guarantee that the file can be edited. If you want, you can learn more about the ICNS file extension.
This is definitely the surest way. Choose one of the programs that support the ICNS file extension, open your file and check the editing options. The most proven method is to download the installer from the developer's website. Links to the websites of software producers can be found on the software subpages. Examples of programs cooperating with ICNS files, which make it possible to edit it.
The full list of ICNS supporters
Most of the file formats are simply text format saved under a different extension - so you can open them e.g. with Windows Notepad However, it's dangerous, you can permanently damage your ICNS file. After saving the changes, it may not be possible to reopen the ICNS file. For this reason, try to use software created to edit ICNS files.
It is actually certain that one of the applications working with files in the ICNS format will be able to edit the file. However, if for some reason you did not find this option, you can try using tools prepared by external websites. Below we found websites that help in editing ICNS files.
Free Online File Edit Service
Copy and paste this link anywhere.