I have two images in a Word document and I cannot delete either one. I have tried delete, fn+delete, and I have even tried to cut and paste to remove, but none of these methods work. Any suggestions?

Both images are PDFs, and one is a vector file and one is not a vector file. On the Format Picture ribbon, the buttons for Filters, Remove Background, and Group are all grayed out.

Another strange thing is that I can select the image and even copy it. I can even click on the image and press Command-X and then paste it somewhere else in the document using Command-V, but the strange part is that when I use Command-X it does not remove the picture -- it simply copies it.

Any advice would be greatly appreciated.