The PTZoom extension may also be used for display of flat images. In this case, an arbitrary but small field of view (< 5°) has to be set, and consistent values for tilt and pan limits. The example was scanned from a 24mmx36mm negative, and I simply chose the image lengths in cm. Pan and tiltlimits are then set to half of these values. Don't forget to adjust the minimum field of view which otherwise defaults to 10°.
Code:

<applet name="ptviewer" archive=ptviewer.jar  code=ptviewer.class width=320 height=200>
<param name=applet0  value="{code= ptzoom.class} 

                            {file=Insert2.jpg}
                            {progress=true}
                            {fov=2.4}">
<param name=inits    value="ptviewer:startApplet(0)">
<param name=fovmin   value= 0.1 >
<param name=panmin   value=-1.2 >
<param name=panmax   value= 1.2 >

<param name=tiltmin  value=-1.8 >
<param name=tiltmax  value= 1.8 >
</applet>