Any suggestions on how to scale a full screen iPad image without losing image quality?

Question

Here's what I'm trying to achieve:

Full screen image of an animal (vector based art, not a photo) on an iPad. When you click on a body part, let's say the ear, the image zooms and recenters on the ear and text is displayed about the ear. Click the zoom out button and you're back to the full body shot. I know how to program the zooming and moving, but I don't know what the best approach would be for handling the image quality. The 1024x768 image needs to zoom by 400% to get the crop effect that I want. Obviously, for the new iPad, that 1024x768 image would already start doubled and have to increase 400% from there.

The initial inclination is to take a 4096x3072 image and start with it scaled down to 1/4, then when you scale in 400%, you don't lose image quality. This one image uses almost 70MB of memory which is expected and I understand why that's happening, but obviously that's not going to fly when this is only one part of a larger app. Let alone what would happen with an @2x version for retina.

Does anyone have any suggestions on how to achieve this effect without putting such a load on the device? It looks like iOS devices can't work with vector images, only rasterized ones. Because of the level of detail I'd like to achieve, I can't just zoom in and deal with the loss of quality. Is this even doable or should I find a different approach? I am working with XCode 4.3.1 and Cocos2d v 1.0.1, but can look into v2.0 if that would solve my problem.

Full body image of my super awesome lemur (I have a graphic designer to do this later):

Zoomed in on the ear:

Once our designer works on it, I imagine something more along these lines (image from google images search, not my work, and hopefully ours won't be so grumpy):

Answer 1

Perhaps you can use multiple images. Have a full-screen completely zoomed-out image. When the user decides to zoom in on some part then display another full-screen image of the zoomed-in part. You can animation the transition (fade in/out) such that it will be sufficiently smooth.

This assumes finite zooming options. For example the user can zoom into n difference places on the animal.