Subject? Object?

[ELTer]

Is 'my sister' the subject, and 'my right' the object here? "My
sister is to my right in the photo."

[Rolex_Cellini]

Is 'my sister' the subject, and 'my right' the object here? "My
sister is to my right in the photo."

"My sister" is the S(ubject).
"to my right in the photo" is an A(dverbial complement) in the copulative construction where the "is" form of "be" is the copulative verb (a.k.a. linking verb).

My sister is to my right in the photo. = SVA