Here's the sticky (link) on how to post a picture. I wrote it, so I know it works. :) https://www.askmehelpdesk.com/dogs/h...re-678901.html
As for your pup, one thing I learned as not only a fur baby parent, but a parent of human babies, follow your gut. If you're really worried then a trip to the vet, or doctor (depends on the baby) is never a bad decision.
White foam vomiting is very common. I won't say there's nothing wrong. Something is wrong. Is it worth a $300 plus trip to the vet? Not unless it continues, and doesn't get better in a day or two.
Just remember one thing. Dogs and humans, we have a lot in common when it comes to illness. Sadly a dog can't tell you "Human, I have a tummy ache. I'm not feeling great".
If he's eating, playful, drinking, and being himself, other than puking white foam, I wouldn't worry. But again, I'm not a vet. Please keep that in mind. I only say it because I want you to know that I can only go by what I've experienced with my pets, I can't diagnose. No one can diagnose online, not even a vet.
You're the mommy of this fur baby. If you're at all concerned, if you're really worried, then a trip the vet is always what I would recommend. Better safe than sorry.