There may have been baby pictures, but items get lost over time.
My baby pictures have all disappeared. The only survivors are one from when I was 6 years old and another from my freshman year in high school.
Because there are no baby pictures, this doesn’t mean my parents aren’t my parents.
That is very uncommon. Most mothers have at least a couple of photos of Mom and baby or Mom and small toddler.
In fact I bet if we did a poll the way FR used to asking who did and who did not have any baby/tiny toddler photos of themselves and their mother, or Freeper mothers who have or do not have photos of themselves and their babies/ small toddlers, about 99% would have such photos.
Of course disasters and loss can happen. But it is not the usual course of events.
And there are many other factors that are suspicious or more than suspicious about Zero’s purported parentage.