The Ken Burns effect is a type of panning and zooming effect used in video production from still imagery.
In Clip tab > Transformation, the X, Y properties which specify the placement could be keyframed as a group, and similarly the Width, Height properties which specify the size could be keyframed as a group. Currently the values remain the same through the entire clip. If they are keyframed it will be possible to drag the overlay UI in the viewer to change the placement of the image or its size at the position of the playhead.
For example you set the initial placement of the image, then enable keyframed transformation, seek at the end of the clip, set a new placement; now you can play and see how the image transitions from the first to the second position.