Understanding 絵に描いたように > **** > In the Dursley family, _who were the very picture of contentment_ , there was just one secret. My translation of is purely a guess based on Jisho's definition of as "The very picture of...". I can't understand how this phrase is used. Literally, I would translate as "Contented as though they had painted on such a picture". So I can kind of see how it works, but what is needed for? Could you give some other examples using this phrase so I can get a better feel for how it works?

modifies , so it means "Such a family, the Dursley family, who were the very picture of contentment, also had just one secret."