In video, DPI means absolutely nothing.
You need to use the Pan and Zoom effect in Avid, or look into using After Effects, Boris Red, or StageTools (an Avid Plugin) for this.
Avid’s Pan and Zoom will do what you want, but won’t rotate. You can do these things easily in Boris or AE if you’re familiar with them, and it will probably take about 3 minutes to learn StageTools if you decide to go that route (a great plugin, but not incredibly cheap).
If you use Avid’s Pan and Zoom, you’ll be limited to 3000 x 3000 pixels if I remember right. So can your photo in to be 3000 x 3000 pixels (or bigger, then crop the bit you need). Leave it this size, and save it as a targa.
Import that picture into Avid and it will resize it. Drop it into your timeline where you want to do the move, then apply the Pan and Zoom effect. Open the effect editor and click the gray button by Pan and Zoom. It will open a box where you navigate to the 3000 x 3000 picture on your hard drive. Keyframe your movement, set it to highest quality, and render (read the help files for more on how the effect works).
Voila! Zoom into pictures without quality loss.
Michael.