Nominal PbSe nano-islands were grown in the Stranski-Krastanow mode on (111) oriented PbTe/BaF2 pseudo-substrates by molecular beam epitaxy (MBE). The number density and morphology of these islands were assessed by means of atomic force microscopy (AFM). Transmission electron microscopy (TEM) was employed to determine the strain state and crystallographic structure of these islands. On the basis of both AFM and TEM analyses, we distinguish between different groups of tensibly strained islands. The suggestion is made to use such nano-islands as part of nanometrology standards for scanning probe microscopy.