1. A system for interactive annotation of an image, comprising: a user input that receives a placement command from a user, the placement command being indicative of a first placement location of a marker in the image, the placement command being obtained by the user using a user interface device to move the marker over the image; and a processor that: applies an image processing algorithm to a region in the image, the region being based on the first placement location, the image processing algorithm determining a plurality of match degrees between the marker and a plurality of image portions within the region, wherein the match degrees are determined based on the image processing algorithm providing a distinct output for image portions that visually correspond to the marker, determines a second placement location in dependence on the plurality of match degrees and the respective plurality of image portions for matching the marker to the region in the image, and places the marker at the second placement location in the image.