A system 100 for enabling interactive annotation of an image 102, comprising a user input 160 for receiving a placement command 162 from a user, the placement command being indicative of a first placement location of a marker 140 in the image 102, and a processor 180 arranged for (i) applying an image processing algorithm to a region 130 in the image, the region being based on the first placement location, and the image processing algorithm being responsive to image portions which visually correspond to the marker 140 for establishing a plurality of match degrees between, on the one hand, the marker, and, on the other hand, a plurality of image portions within the region, (ii) establishing a second placement location in dependence on the plurality of match degrees and the respective plurality of image portions for matching the marker 140 to the region in the image, and (iii) placing the marker 140 at the second placement location in the image 102.