app.js

var win = Ti.UI.createWindow();
var images = [];

for(var i = 1; i < 100; i++){
   // Assuming all the images are called image1.jpg, image2.jpeg, etc...
   images.push('/images/image'+i+'.jpg');
    
}
var gallery = Gallery(images,0);

win.add(gallery.view);

win.open();

gallery.js

function Gallery(images, startAt) {
    images = images || [];
    startAt = startAt || 0;
    var views = [];
    var imgs = [];
    
    for(var i = 0, len = images.length; i < len; i++) {
        var zoomable = Zoomable(images[i]);
        views.push(zoomable.view);
        imgs.push(zoomable.image);
    }
    
    var scrollable = Ti.UI.createScrollableView({
        views: views,
        currentPage: startAt
    });
    
    return {
        view: scrollable
    }
}

zoomable.js

function Zoomable(image) {
    var scroll = Ti.UI.createScrollView({
        width: Ti.UI.FILL,
        height: Ti.UI.FILL,
        contentWidth: 'auto',
        contentHeight: 'auto',
        
    });
    var image = Ti.UI.createImageView({
        image: image,
        width: Ti.UI.SIZE,
        height: Ti.UI.SIZE
    });
    
    function onLoad() {
        image.removeEventListener('load', onLoad);
        
        var ratio = 0,
            width = image.rect.width,
            height = image.rect.height;
            
        if(width > height) {
            ratio = scroll.rect.width / width;
        } else {
            ratio = scroll.rect.height / height
        }
        scroll.minZoomScale = ratio;
        scroll.zoomScale = ratio;
        image.image = image.image;
    }
    image.addEventListener('load', onLoad);
    scroll.add(image);
    return {
        view: scroll,
        image: image
    }
}