Let's suppose that you have an image of some graph (for example, it may be scanned paper image, a picture from the PDF file or another picture format that has only graphic representation), and you wish to digitize curves from this graph. In this case you should use DM2003 Digitizer window (see picture below).
Convert the image to be digitized into the bitmap or WMF format and load it into Digitizer window (you may open disk file or paste image from clipboard). Note that plot axes must be strictly vertical and horizontal, otherwise you should rotate image in any graphic processor (like Microsoft Windows Paint).
Define plot coordinates: press "Draw Frame" button and move frame to coincide with labeled ticks of the graph and set appropriate axes ranges. If your image has log scale, you should specify logarithms of the axis limits (as shown on the picture above) and correct data later using Process|Calculation|Recalculate Data Range operation.
Press "Add Points" button and click somewhere in the Digitizer workspace to add points. You also can delete and move points. After you draw all points click OK button to save them in the active data window (Process|Digitize menu item is disabled if there's no active window available).