Since the zoomable image tag is exclusively used for pixel art it might be a good idea to use css attribs which make the image resize with a nearest neighbour algorithm.
It uses this (http://custom.simplemachines.org/mods/index.php?mod=930) plugin. If you want to work out how to make it do that, then by all means let me know how and I'll implement it.
in modification2.xml change the function below:
function setZoomLevel(obj, lvl)
{
obj = obj.parentNode.parentNode;
img = new Image();
realImg = obj.getElementsByTagName("img")[0];
img.src = realImg.src;
realImg.width = img.width * lvl;
realImg.height = img.height * lvl;
obj.style.width = realImg.width + "px";
obj.style.cssText += "image-rendering: -moz-crisp-edges; -ms-interpolation-mode: nearest-neighbor;";
}
untested but that should work.
[imgzoom]http://www.adventuregamestudio.co.uk/forums/Smileys/AGS/smiley.gif[/imgzoom]
Looks pretty good to me?