If you wish to add a custom icon for your components (eg. a transformer or analyzer), you need to place the icon as a PNG image with the same name as the fully classified class name of the component.

An example: If your component class name is "com.company.ext.MyAnalyzer", then the icon for this component should be located at "/com/company/ext/MyAnalyzer.png" in the extension JAR file.

Similarly, if you bundle your own ComponentCategory implementations (which define the menu groups in DataCleaner), you can define icons for these by adding a PNG file with a fully classified filename corresponding to the ComponentCategory class name.