This collection includes optical monitorings of gravitationally lensed quasars. The frames can be used to make light curves of quasar images and field objects. From quasar light curves, one may measure time delays and flux ratios, analyse variability and chromaticity, etc. These direct analyses/measurements are basic tools for different astrophysical studies, e.g., expansion rate of the Universe, mechanism of intrinsic variability in quasars, accretion disk structure, supermassive black holes, dark halos of galaxies (dust, collapsed dark matter, smoothly distributed dark matter,...)