In the case of picture insertions, such as picture-in-picture, for example, fluctuations in the line duration are manifested in position displacements relative to the desired position of the inserted pictures. In order to prevent position displacements in the horizontal direction, it is provided that the insertion position is corrected in a manner dependent on a determined line duration. The method according to the invention is suitable in particular for picture-in-picture insertions in television receivers.