well they are definitely bugs ^^
Jokes aside, I have no idea how an image file would be a virus. They could be more descriptively named though.
You can export a GDocs document and generate the PDF from LibreOffice, that should have bookmarks. Or maybe there are tools to do this automatically: https://stackoverflow.com/questions/30304718/create-bookmarks-into-a-pdf-file-via-command-line