We have long been interested in presenting sequences of polarization sensitive VLBI (Very Long Baseline Interferometry) images as ``magnetic movies'' to show the evolution of the parsec-scale magnetic field in the jets of blazars. Early VLBI polarization experiments revealed complex magnetic field structure in these sources with dynamic polarization properties on short time scales (e.g. Brown, Roberts & Wardle, 1994) and intra-day variability has been observed in some sources (Gabuzda et al. 1989, 2000a,b). Now, instruments such as the NRAO1 Very Long Baseline Array (VLBA) and the Very Large Array (VLA) are routinely used to rapidly monitor changes in source structure in a variety of radio sources, making movies of these objects possible.
Here we present our method for making total intensity and/or polarization movies from multi-epoch radio observations. We focus especially on the issues specific to polarization sensitive images. This procedure has been implemented in a script in NRAO's AIPS package, and we have applied it to make some ``superluminal magnetic movies'' (section 3).