The long-period RS CVn binary IM Pegasi II. First surface images

New high-resolution, high signal-to-noise ratio spectroscopic observations and UBV photometry carried out in 1996-1999 were analysed with the surface imaging technique. A total of 8 images of IM Peg was obtained for the first time. A huge high-latitude active region was found to dominate the stellar surface and decreased in area during the period of the observations. At th e same time, on the opposite hemisphere (in longitudes), smaller spots were developing. The spots were migrating in the orbital reference frame, the p eriod of spot rotation being of 24.(d)73+/-0.(d)02. The spots constitute tw o active longitudes on opposite stellar hemispheres, similar to other RS CV n stars. The evolution of the spot areas within the active longitudes indic ates a stellar activity cycle, during which one active longitude dominates the stellar activity, to be about 6.5 years. Then, a total cycle, comprisin g two consecutive periods of activity of both active longitudes, is about 1 3 years. In 1999, the activity switched to the other active longitude. This declared the beginning of a new (half-) cycle.