blackest.. the link you give is to a stock photo.
Professional photographers advertise their pics on different sites in the hope people will buy them for magazines /cards etc. to earn them money
They see a pretty tree with blossom and just add a name ... such as "beautiful japanese cherry."
However, very often the labels are vague.
Certainly you cannot trust it as botanically accurate.
Prunus cerasifera nigra often has red leaves in summer.