  This paper is devoted to nonlinear resolvents of holomorphic generators of
one-parameter semigroups acting in the open unit disk. Since the class of
nonlinear resolvents consists of univalent functions, it can be studied in the
framework of geometric function theory. In this way, we complete and enhance
the previous results proved in \cite{E-S-S}. More precisely, we establish some
distortion and covering results, find order of starlikeness and of strong
starlikeness of resolvents. This provides that any resolvent admits
quasiconformal extension to the complex plane $\C$. Also, we obtain some
characteristics of semigroups generated by these resolvents.
