This is a known issue in Microsoft Word. It can occur when images are pasted into Normal view and have a wrapping style other than "in line with text." Word contains separate drawing and text layers. When an image is inserted into a document as float over text, it is inserted into the drawing layer. In Normal and Outline view, this drawing layer is not visible, and therefore, the image is not either.
Select a view option other than Normal or Outline view. To change the view, select a view option from the View menu.
Change the picture formatting layout to "in line with text" while in Normal view. To do this, choose Tools > Options > Edit tab. Select the In line with text option from the Insert/paste pictures as dropdown list.
Enable the Drawings option. Choose Tools > Options > View tab > enable Drawings.
Disable the Picture placeholders option. Choose Tools > Options > View tab > disable Picture placeholders.