Some of the records have push-pin identifications attached to them. This facility is available on a particular picture if the little push-pin icon appears in the top left corner.
The list down the right hand side now shows the list of identified points on this picture (usually names of people). Click on one or more of these names to cause a pushpin to appear on the relevant part of the photo. As many of these can be displayed as may be required, and they can be individually cancelled by clicking on them again.
Similarly if the cursor is hovered over a particular point on the picture, then any push-pin which has been identified at that point will be displayed.