Highlighting can be performed in the PDF editor either at a document level or bundle level. More guidance on opening documents or bundles in the PDF editor can be found here.
With your document open in the PDF editor, first select the "Image" tool in the ribbon, and select "Image".
When the image tool is selected, an explorer window will appear allowing you to select an image file from your local machine. After selecting an image, this will be placed on your PDF. You can then select the image to move and resize.
