This issue has come up recently on the Slicer forum (https://discourse.slicer.org/t/adding-an-icon-to-identify-an-extension/30562/8).

CLI modules actually can already store icons, but they provide it on their standard output when the CLI module is launched with the --logo argument. It would be very inefficient to simply start using this feature, as it would mean running 50 executables at each Slicer startup to just get the CLI module icons. We would need to do something like that is done for the module description .xml files cache the icon files in the module folder so that the application can load them directly. Even then, loading 50 icon files may have add some perceivable delay at application startup. Maybe adding the icon to the .xml file would be faster (as we already load the .xml files at startup)?

Another complication is that it is not trivial to bundle the icon file into the executable file (embedding binary resources into an executable is different on each compiler).

Exploring all the options and implement something that does not slow down application startup and remains compatible with the existing CLI module infrastructure would be quite significant work. Since the benefits are quite small, this issue remains low priority.

For reference, the file vtkKWResourceUtilities.cxx mentioned in the original issue is now available in the NA-MIC/svn.slicer.org-Slicer3-lib-mirrors@trunk mirror¹

For reference, here is a comment originally posted in https://mantisarchive.slicer.org/view.php?id=2072#c4931 / #2072

A GitHub project named "ImageToHeader" could be created in github.com/Slicer, the associated code could be copied (ideally the associated history should be extracted) from ¹, ² and ³

This project could probably be a git submodule of SlicerExecutionModel

Related issues:

• Document / improve mechanism allowing to specify logo(s) associated with CLIs #2072