miniature horses is not a actual breed. just a height breed, and any horse that measures under 38 inchs tall is then classified as a miniature.
however mini horses do come in 2 classes.
class A 34 inch and under
class B 34-38 inch
theres 2 registrations, AMHA & AMHR
they also have 2 body types, draft and Araby, or heavy and refined.
And unfortunately you absolutely cant tell if that mini is a falabella or even a blend without paperwork proving so.
however i can tell you she looks to be class A from this picture and is definitely a grulla in color. which is a dun colored horse and can see her barring on her legs. she also has a dorsal strip down her spine. And from the pic, looks pretty nice in conformation.
if no paperwork/pedigree, she is just a "grade" mini. thats all.