How to show a picture in adsense with empty ads as well?

Question

Google Adsense

Google often cannot find an advertisement and it turns out that the place of the block is empty.
How to do it and where is it done so that instead of empty spaces it was possible to put a picture according to the size of the block?

Answer 1

The picture uses AMP, but the question is not about that. You can use the data-alternate-ad-url option to add a stub.