I don't really have any pics. In answer to your questions -
1) not really.
2) definitely NOT
3) great big YES
Piebald is a recessive trait. If it had a consistent marker, it wouldn't be recessive, it would be co-dominant. The only ways to know for sure is to
a) produce it yourself from a homozygous animal
b) 100% completely trust the breeder that did produce it
c) prove it through breeding.
d) develop a dna test that shows it.
Steve