A family of Microsoft word processing software products for creating web, email, and print documents.
As others have suggested, you need to provide specific, detailed information including where you're copying from, what you're copying, which browser you're using [what gets captured when copying depends on the program being used] & the exact steps you're taking.
I, also am using v16.71 of Mac Office & Firefox on Monterey 12.6.4 but have no problem as indicated by this screen shot:
BTW: Picture Placeholders are not available in Mac Office but they have no bearing on this issue whatsoever.
One other thought: Make sure you are using Print Layout View. Images do not display in Draft ot Outline View.