My milk has consistent microfoam. This seemed to be from the crema...
...or a high acidity bean. What coffee is it?
(and when was it roasted)
i'm going for high acidity too combined with the fact that it took you a little while between pouring the milk and getting your camera out so the coffee had time to go "off".
what milk are you using? high acidity + most soy milks = tofu blooms. this isn't a tofu bloom and i doubt you're using soy, but that's another fairly common source of mottling and bubbling on the crema of a milk drink.
It probably is from letting it settle a bit before taking the photo. I also find you can eliminate that by breaking the crema up slightly with the way you introduce your milk, or just swirl the espresso in the cup for a couple of seconds to loosen everything up (it turns creamy gold) then pour the milk.