ClipToIconCM is a contextual menu plug-in which adds custom icons to files using pictures on the clipboard.
Suppose you have a file with a generic icon such as:
You can add a custom icon to this file using ClipToIconCM by first putting an image file on the clipboard. For example, you could use your web browser to find a web page with the desired graphic and then use "Command-Control-Shift-4" to select a portion of the screen to "capture" to the clipboard:
In the Finder "Control-click" on the file you want to add the custom icon to, and select the menu item named "Clip to Icon" as shown:
After processing completes the file's new icon will match the picture you put on the clipboard: