Is an imine considered a secondary amine?
No. Imines cannot be considered an example of secondary amines any more than pyridine can be considered a tertiary amine.
The easiest way to think about this is with oxidation state: imines are at a higher oxidation level than amines, just as aldehydes are at a higher oxidation level than alcohols.
Aside from this 'intuitive' explanation, the IUPAC gold book (a source of chemical nomenclature) defines both amines and imines, clearly differentiating the two:

amines. Compounds formally derived from ammonia by replacing one, two or three hydrogen atoms by hydrocarbyl groups, and having the general structures $\ce{RNH2}$ (primary amines), $\ce{R2NH}$ (secondary amines), $\ce{R3N}$ (tertiary amines).
imines. Compounds having the structure $\ce{RN=CR2}$ (R = H, hydrocarbyl). Thus analogues of aldehydes or ketones, having NR doubly bonded to carbon; aldimines have the structure RCH=NR, ketimines have the structure $\ce{R'2C=NR}$ (R' ≠ H). Imines include azomethines and Schiff bases. Imine is used as a suffix in systematic nomenclature to denote the C=NH group excluding the carbon atom.