Such data (non dicom) have no meta information, so “Add DICOM Data” menu does not recognize them.
Instead of “Add DICOM Data” you should use menu “File > Add Data” to load non-DICOM images.
@fedorov Thanks–I just tried to load a png file, but got such error:
Error: Loading /xxx/Pictures/4.png - load failed.
You may wish to consider using Imagej software in conjunction with the plugin, Annotator J.
Fiji Imagej download:
I’ve never come across a png image that Slicer could not load. Could you upload your image somewhere and post the link here?
If you need to annotate 2D microscopy images then indeed ImageJ (FIJI) could be a good choice (although it uses a restrictive (GPL) license and it is based on Java), or perhaps Napari is even better (it uses non-restrictive license and based on Python). Of course you can also use Slicer for 2D images, but Slicer’s unique strength is in working with 3D data (images, meshes, transforms, 3D annotations, etc.).