Hi Jian,
Yes - the control does support EMF/WMF (metafile) embedded images, which are particularly useful when you create export to PDF as those types of images can be freely scalable. The following example shipped with the control shows how to include metafile images inside paragraph content:
Text Editor \ Model \ Inlines \ Image Inlines.
Hope this helps - let us know if you meet any problems or have any questions.
Best Regards,
Nevron Support Team