Custom icons for files or folders

I iconize a folder with the following script

#!/usr/bin/env python
import Cocoa
import sys

Cocoa.NSWorkspace.sharedWorkspace().setIcon_forFile_options_(Cocoa.NSImage.alloc().initWithContentsOfFile_(sys.argv[1].decode('utf-8')), sys.argv[2].decode('utf-8'), 0) or sys.exit("Unable to set file icon")

Gist

Executing by running:

python set-image.py "locationtopngyouwanttouse.png" fulllistingtofolder

eg

python set-image.py Office-2016-Office.png /Applications/Microsoft Office 2016/

I had that happen to me once. Within Composer, make sure the permissions on the icon file are set to Read for all.

I came along this question and tried out the idea of @AVmcclint. It also worked out for me! 👍
The problem was that I removed the icon-file from the created package in Composer.

I added the picture with copy-paste method in the Finder > Information window.
So just open the picture, copy and paste it on the Foldericon. After that I checked the privileges in Composer, the Icon file is not present for the users but works as folder icon 🙂