John Deerfield , Mar 08, 2011; 01:51 p.m.
Well, a DVD is 720x480 (rectangular pixels). That's it. Period. If nothing else, the compression engine is going to compress the video to 720x480 pixels. As to what size the image should be prior to that depends on the editing. If you are doing a 2x motion keyframe (sometimes called the Ken Burn's effect) where you "zoom" in 2x on a slide (not counting transitions), then you might want a resolution of 1440x960. The only thing a widescreen DVD is doing is chopping off pixels at the top and bottom pixels to achieve a "wide screen". So now you are dealing with the same resolution (720x480) only it chops off the top and bottom of your image to give you a wide screen... so now your actual image has less resolution.
PAR [pixel aspect ratio] pixel aspect ratio of 0.9 on a normal sized screen
You might be over thinking things a bit. Once you define the resolution of your image, let Premier handle "how it should look". A pixel aspect ratio of .9 means nothing to me. What is a normal sized screen? Physical size of the TV isn't relevant. A 20" standard definition TV (a DVD is standard definition) is 720x480 pixels. A 50" TV is 720x480 pixels.
I think it is important to understand that video editing and compression was designed for motion graphics. As such, I usually find it beneficial to keyframe each image so that it has motion. Say the image starts small and finishes large. You could then copy this keyframe to all the other images (unless you wanted each image to have it's own unique keyframe). In terms of getting the color, saturation, and so on that you would like to have, at some point you just have to let go.
with poor detail in the shadows and highlights
And? Again, at 720x480 pixels, this isn't a print competition where judges are looking for details in the shadows and highlights. A DVD is low-resolution. Furthermore, it is compressed for motion. If I am doing a slideshow, I just set my timeline up for a standard NTSC. If the slideshow is being played on a widescreen TV, the TV itself usually has settings that allow the image to "fit the screen" if that is the intention. And keyframing some motion keeps the viewer involved in what it unfolding as compared to discussing the highlights and shadows of a still image!