[IceHand]

I've fixed the zooming issue (see changelog), but I'm unable to see a reduced image quality. Could you describe how the quality got worse and/or show a screenshot?

By the way, I forgot to add the rotate option, I'll do that later today.

EDIT: To explain the default 83dpi setting: it's half of the real resolution of the Cybook, so setting it to 83dpi will give you the real image size in pixels at 50% zoom. That means the whole page when the image is resized to 600x800 (default), as the Cybook has a resolution of 600x800 at 166dpi. You're then able to use zoom.
Notice however that when zooming in on an image with a 600x800 resolution, you'll notice pixellation as the Cybook needs to resize up. You could set the resolution to e.g. 768x1024, when you know beforehand that you want zooming. However if you do that, the image sharpness when viewing the whole page is a bit worse, because the Cybook needs to resize down.