Photo evidence is good.
You may need to force your dog's return by sending a demand letter threatening legal action and/or going to court to seek their return.
Here is a good (albeit older) look at dog ownership and the laws in California, by William McCarty Niall, provided by Michigan State University's College of Law Animal Center:
https://www.animallaw.info/article/animal-law-california
You will want to arm yourself with all the evidence you have proving you are the dog's owner - this will include not only photos but vet bills (vaccinations, etc).
The puppies, even if you have found homes for them, are not yet old enough to be separated from the mom dog.
Good luck.