It is possible to use yEd's properties mapper to set the icon of a label. For this to work, the path to the icon file has to be stored in your diagram's custom properties. Moreover, the exact setup depends on how you store that path.
E.g. if you have a GEDCOM file with OBJE tags like so
0 @I1@ INDI
...
1 OBJE
...
2 FILE /absolute/path/to/image.jpg
Then the following properties mapper configuration will work: