In Foxit Reader,you could only use the Image Annotation tool which is under the Home tab to add images. So that images that added with Foxit Reader are actually some image annotations rather than the real image objects in file’s content layer.
Not all PDF viewers support displaying image annotations. If you happen to open a PDF file using a software that does not support displaying image annotations, then the image annotations will not be displayed there.
When you need to add real image objects in PDF document’s content layer,we could choose to use the Add Images tool under the Edit tab in Foxit PhantomPDF to add them.
You may also convert the image annotations into real image objects by using the Flatten tool under the Organize tab in Foxit PhantomPDF.