// resize the imageview blob, width and height have to be explicitly set
function getResizedBlob(_blob)
{
    return _blob.imageAsResized(165, 100);
}

// create the window
var win = Ti.UI.createWindow({
    backgroundColor : '#fff'
});

// create the initial imageview
var image = Ti.UI.createImageView({
    image : 'image165.jpg',
    left : 0,
    top : 0,
    width : 165,
    height : Ti.UI.SIZE,
    backgroundColor : 'red'
});

// pass in the resized image into the imageview 
image.image = getResizedBlob(image.toBlob());

win.add(image);
win.open();