Scrolling wide aspect ratio image on powerpoint slide

Looks interesting... I'll have to play with it but I suspect it is not exactly what I am looking for.  It looks like this method will still require the image to move along a predefined path.  I need to have the ability to arbitrarily initiate, stop, and even reverse the motion. Perhaps if I reveal a little bit more of my motives for this it will become clearer.
The "images" are actually output strips from a medical diagnostic device.  They are not EKG but for the purposes of this discussion they may as well be.  The presentation will be used for instructional purposes with the powerpoint slide emulating the output of the device.  It is important to view the images chronologically from left to right as if they were coming out of a machine on a paper tracing. Part of the insrtruction would include stopping the motion to discuss what is being seen and to make predictions about what is likely to come.  Conversely, it is also necessary to occasionally "go back" in time after seeing the outcome to look for clues that would predict that outcome.

BTW, this type of instruction is currently accomplished by obtaining physical paper strip tracings and dragging them back and forth trough the field of view of a document projection system... very cumbersome.

The very easiest method for you to do this is to span the picture across multiple slides.  Insert your image on the slide align it to the left side of the slide and using the cropping tool, crop off all the picture that goes off the slide.  Your first "piece" should fit exactly on the slide.  Now click on Insert, Duplicate Slide.  On the second slide, move the picture so that the right side is aligned with the left side of the slide.  The picture should be complely off the slide.  Now use the clipping tool to expand the right side of the picture all the way to the right side of the slide.  Use the clipping tool to clip off the left side of the image.  Repeat until your entire image is in your slideshow.  Make sure these slides have transitions set to none and uncheck the Advance on mouse click box.  Now when you run your slideshow you can use the left and right arrow keys to "scroll" back and forth through the picture.

For analternative, there's a clever drag and drop macro that would work if your presenter has a steady hand:
http://joedale.typepad.com/integrating_ict_into_the_/2006/10/drag_and_drop_i.html
http://www.deadgekko.co.uk/downloads.htm

You could also consider making scrollable Flash files from the images (if you have the skill or the tools) and embedding those in the presentation.  There's a tutorial here: http://www.tutorialized.com/tutorial/Scrolling-A-Movie/3087

Oh yeah, in the spanned across multiple slides method, you could add the action buttons for Next Slide and previous slide.  And a really cool way to do this would be to make the slides a custom show and hide the slides.  Then you could add a button to your presentation to "view output strip" and set it to Show & Return for the custom show.  In fact, I like this idea so when I think I'll write a tutorial for it.
Thanks!
:-)

Well darn, forgot to account for making it look like it's scrolling.  You have to have the action buttons to make it work.
Here's how it's done:
Add a Next and Previous button on each of your slides except the first and last slides should only have a single Next or Previous button.  Now Insert duplicate slides for every slide except the last one.  Set the slide transition animation for every other slide to PUSH LEFT (for example, slides 1, 3, 5, 7, etc.) and set the slide transition animation for the remaining slides to PUSH RIGHT (for example, slides 2, 4, 6, 8) Set the Last slide to a transition to PUSH LEFT (you don't need to duplicate this slide).
Now on slide 1 & 2, set the Next button to jump to Slide 3 (Since these are both the first slide they should only have a Next button).  On slide 3, set the Next button to jump to slide 5 and the previous button to jump to slide 1, on slide 4, set Next to slide 5 and Previous to slide 2.  Repeat this pattern for the remaining slides.  The previous button on the last slide should be fine as is.
Now the effect will be scrolling back and forth.  Lots of extra slides to create the effect, but it looks very cool and was realatively easy to do without requiring VB.

Ok - you've given me many things to try.  So far, it appears that any of the purely powerpoint solutions (i.e. motion paths, or splitting the image onto multiple slides with push left/push right transitions do not produce the quality I am trying to achieve.  I am convinced that it is going to take either a VBA macro  or an embedded ActiveX control to achieve the desired result.

I have been playing with the click and drag macro... By commenting out a single line of code I was able to restrict motion to X axis only thus achieving the ability to drag left and right without affecting vertical position.  The difficulty I now face is that the macro functions such that the first click will snap the image's centroid to the click postion.  It is therefore not possible to grab the image by an edge, set it down, move the cursor over, click to grab the image again and continue the move.  I cannot tell if this is by design of the code or not.   I'll have to play with it some more.

As for embedding a flash movie player, or for that matter Windows media player... They both require creation of a movie of the scrolling image in advance.  This is not terribly difficult to do but also causes the motion to be predefined.   It sure seems like there should be an embeddable ActiveX image viewer with scroll bars that would allow simple left/right scrolling of the image.  Any ideas?

I think this is (if not exactly) almost exactly what you're looking for:
http://radiographics.rsnajnls.org/cgi/content/full/23/6/1683
Download the ppt just as you did for the drag and drop ppt.

If your images aren't DiCom, you can use consider using the internet browser ActiveX control to scroll the images.  Easiest way to do it is with the LiveWeb add-in:
http://skp.mvps.org/liveweb.htm
Just list the file location as the web address.

Glenna - I really appreciate all of the thought you have put into this but it starting to look like we are grasping at straws.  From the standpoint of portability and function, it is beginning to look like a solidly written VBA macro is the way to go.    I'm going to go ahead and accept your initial response as a solution so you get your points but please feel free to add more comments if you get any new ideas.

Here's a code snippet to get you started:
http://billdilworth.mvps.org/large_scale_image_scrolling.htm

I'll keep looking and post back when I can.

Thanks - And now I have come full circle... The site you just referenced is where I began this effort in the first place.  

One last suggestion for you:
http://www.indezine.com/products/powerpoint/ppqtvr.html
Change your image to a VRML panorama and embed it.  This link directs you to all the software/info you need and it should allow you to acheive exactly what you're trying to do without having to write all the code yourself.
Apple has a QuickTime ActiveX control that you may be able to use: http://developer.apple.com/quicktime/compatibility.html