Another program that illustrates this effect is MotionPicture, available at:
I tried it, and I think it's very cool! I highly recommend people check it out.
Mac OS X and Windows Vista are already using this effect in their viewers, so it's getting to be more and more common. (But I don't have Vista!)
MotionPicture creates the effects by creating combined pan/zooms, but these combinations are basically random. By contrast, I've also recently tried the program Zoom Studio. It's not a slide show viewer, but it animates individual images using Ken Burns effects. The difference is that Zoom Studio allows you to control the effects in a precise way. It's available at:
Until I saw these programs, I'd assumed these kinds of effects weren't even possible in real time (not smoothly, at least). I would love it if XnView could implement these kinds of effects.
I note that MotionPicture requires a geForce or better graphics card. This suggests to me that it's sparing the CPU by shifting the load of the graphics operations to the graphics card, explaining the smoothness of the effects. (They look great even on my 733 MHz machine.)
What I'd really like to see in an image viewer is the ability to control some of these effects with the mouse or keyboard.
For example (ignoring existing key assignments for a moment) CTRL-<right> might tell the program to start a pan to the right. Then the image would slowly start panning smoothly to the right. The speed of the pan could be set by the user.
Smooth zooms could be controlled in a similar way.
With some thought, one could find ways to implement simple commands to initiate pan movements at user-controlled angles(not just left, right, up and down), and smooth zooms to user-set endpoints. For example (again, ignoring keyboard assignments), if an image is already panning to the right, pressing down arrow could cause the image to start panning down and to the right. The more you press the down arrow, the more severe the downward angle. Or you might achieve the same kind of effect with mouse commands.
Ideally, it would be cool to be able to save these controlled pans and zooms with the image so that they could be incorporated into slideshows. For example, you might press "record", perform pans/zooms, then press stop, and be able to save these operations with the slideshow. Sounds ambitious, but ZoomStudio already does this with individual images, so it is doable. Also, it would take things a step beyond what's apparently already available in Windows Vista and Apple OS X.