No, it is her own rendering of well-known works.
Although the art-piece itself is her own work,
the design, idea, and copyright go to the original artist.
dA doesn't mind if you post your own representation of another artist,
but you cannot have another artist's respect and acknowledgement without sourcing.
These works may just be school projects, since copying famous artists while in
high school is common for art teachers to have their students practice,
but that does not give the artist copying the original works the right to post without credit.
There is a fine line here, so many may have different opinions,
but I don't think she needs to take it down- just source her work. c: