Annotation can be text, markers such as arrows, freehand drawings, etc.  Image annotation is tied to the actual image and will (supposedly) change with the image manipulation features such as zoom, flip, rotate, etc.  They are mostly used to identify findings in the image.  Screen annotations are not necessarily related to any particular area in the image but could contain general comments and are displayed, for example, on the bottom on the screen, not subject to any image manipulations.

• Image Annotation , screen annotation , annotation