Not quite.
Currently the contained sources support all ImageIndex properties of the standard VCL controls, whatever they are named (f.i. TButton). This is done in ImageIndexMapper.Basics.pas which implements and registers wrappers for each of these components. It should be not too difficult to expand this to other components as well.
It should also be easy to support other TCustomImageList descendants. This can be implemented either in the imagelist component directly by supporting the INameMapping interface or by registering a wrapper class like shown in ImageIndexMapper.PngImageList.pas. The latter exist only to show the mechanism, while the recent version of PngComponents makes use of the former technique.